Despite the fact that the plots of the games usually appear barebone, ''VideoGame/MetalSlug'' has its fair share of characters, all of whom have a great deal of backstory to them. The backstory to each character is where the real plot points stand out.

Characters who debuted in ''Metal Slug Defense'' and ''Metal Slug Attack'' can be seen [[Characters/MetalSlugDefense here]].

[[foldercontrol]]
----
!Protagonists (Broken down by game appearance)

!!''Metal Slug''

[[folder: Marco (Marchrius Dennis Rossi)]]

Marco joined the military's vocational school following technical high school, and after graduating, joined the Peregrine Falcons Squadron, soon becoming its leader. Though generally a good-natured guy, he tends to flip his shit whenever Morden is mentioned, given the fact that Morden was responsible for the deaths of many of his good friends.

Off the battlefield, Marco is an expert computer technician, often creating computer viruses for fun, but one in particular that unintentionally made its way onto the net infected the military's mainframe, made it past all of the firewalls and almost caused the launch of several nuclear missiles. He intends to take that secret to his grave.

From Metal Slug 6 onward, Marco's unique ability is to deal double damage with his handgun. If playing on Easy, though, this ability transfers over to the automatic Heavy Machine Gun. In Metal Slug 7/XX, he can also use the Burst Shot, which allows for rapid fire, though he can't move.

!!Marco Rossi's Tropes:

%%* TheAce
* AllAmericanFace: More or less designed as the typical American war movie hero.
* BerserkButton : Anything involving General Morden.
* BigNo: He lets out one for his death cry.
* BoringButPractical: His ability in the later games is dealing double damage with a handgun. While this is hardly flashy, it's invaluable whenever you're without any upgrades. In ''Defense'', his special is to shoot his Heavy Machine Gun, which is hardly flashy but a good all-purpose skill.
* EagleLand: He's a tanned, blonde-haired American who loves big guns and justice.
* EmergencyWeapon: Starting in ''6'', he is focused on making the starting peashooter of a handgun not so pathetic. By dealing double damage, it's actually pretty decent. Another weapon is still preferable, but not as much.
* ExtendoBoxingGlove: An alternate melee attack for when he's crouching.
* {{Handguns}} : His attack power is doubled while firing a handgun.
* TheHero: The leader of the team and the poster boy of the series.
* HeterosexualLifePartners: With Tarma, who has been with him since the very beginning.
%%* NiceGuy
* OpenSaysMe: An alternate melee attack when he opens chests is to simply kick them open.
* OverprotectiveDad: Put a programming lock on ALICE to keep certain ďadultĒ terms, particularly those dealing with charm and seduction, from even entering her vocabulary.
* PlayfulHacker : During his spare time. He accidentally almost launched nuclear weapons at one point.
* TheSmartGuy: Outside the battlefield he's an expert hacker.
* TrulySingleParent: He's the "father" of [=MS-ALICE=].
* VitriolicBestBuds : With Tarma
* WeaponOfChoice: The Heavy Machine Gun, but initially it was the standard Pistol.
[[/folder]]

[[folder: Tarma (Tarmicle Roving III)]]

Son of a military man, he entered the Special Forces Training School after finishing junior high. At age 20, he joined the Peregrine Falcons on a mission to rescue the president, at which point he met Marco, the two becoming fast friends. When he found out Marco had been selected to take part in the counteroffensive against Morden, Tarma was quick to volunteer. Though he often pokes fun at Marco, he holds his friend in the highest regard.

Whenever he's not engaged in battle, he builds custom motorcycles with such attention to detail that he puts most professionals to shame. If and when he can retire from active service, he intends to open his own motorbike shop.

Tarma's engineering skill from Metal Slug 6 onward allows him to make better use of the Slugs that he comes across. They can take twice as many hits, he can use the vulcan fix, the vulcan's damage is increased, and he obtains twice as many Slug Shells on pickup. In 7/XX, he can also kick Slugs, which can either recover or damage them. However, the double durability and recovery/damage kick only works on Vehicle Slugs.

!!Tarma Roving Tropes:

* AcePilot: His specialty on the team starting in ''6''. He's the best at handling vehicles and it translates to gameplay as tougher vehicles, stronger weapons in them, and new abilities.
* BadassBiker: Off-screen. The CoolShades and his backstory of expertly building bikes establish him as this.
* CoolShades: Never seen without his shades. It also helps distinguish him from Marco at a glance.
* DemotedToExtra: Becomes a supporting character in ''4'', but regains his playable status in ''5''.
* GadgeteerGenius : He's the team's Slug expert, largely due to him tinkering with vehicles in his spare time.
* GlassCannon: In ''Defense'', he has the lowest HP of the four main characters but his Shotgun does the most damage.
* HeterosexualLifePartners: He's the only character who has been with Marco from the beginning.
* MeaningfulName: As the Metal Slug technician of the team, his name last name is ''Roving.''
* TheLancer: Marco's best friend and foil, as well as the default player 2.
* PercussiveMaintenance : His Slug Kick. Sometimes averted, causing damage to the Slug instead.
* PrecisionFStrike: He lets out a huge F-Bomb as his death cry when killed.
* VitriolicBestBuds : With Marco.
* WeaponOfChoice: The Shotgun.
[[/folder]]

!!''Metal Slug 2''

[[folder: Eri Kasamoto]]

Eri was found abandoned on the steps of a church. When she became wise to the ways of the world, she eventually ran off and became the leader of a gang of street kids. The Intelligence Department of the Regular Army noticed her leadership skills, and thus recruited her. She went on to receive spy training, and took part in a number of missions requiring assassination. She found these types of missions distasteful, and requested a transfer to the SPARROWS division. Given her impressive track record, it was approved. Once transferred to the SPARROWS division, she was assigned the role of team demolitions expert.

Given Eri's background of growing up among street children, her demeanor and attitude in life mostly boils down to "Rely on nobody but yourself."

Eri's unique talent from Slug 6 onward is handling grenades. She starts each life with 20, gains double grenades on pickup, deals more damage with them, and is the only one able to aim her throws, which includes straight upward.

!!Eri Kasamoto Tropes:

* ActionGirl: Kicks as much ass as any of the men.
* BareYourMidriff: Setting a trend, her military "uniform" exposes her belly.
* BrutalHonesty: In her first mission with Fio, Eri was blunt saying that her inexperience in combat was going to get them both killed, and that Fio was better hanging back so Eri could go on alone.
* TheBigGirl: While the whole team packs plenty of power, she's the explosives specialist.
* CompressedHair: Hidden in her bandana in her sprites. Some pieces of official art would have some of her hair spew out of her back head.
* DarkAndTroubledPast: We need to reiterate that her old career as an espionage agency assassin was somehow so "distasteful" that she compared it unfavorably to ''blowing people up with grenades and flamethrowers''.
* DemotedToExtra: Becomes a supporting character in ''4'', but regains her playable status in ''5''.
* HeterosexualLifePartners: With Fio.
* InformedLoner: She's on a four person team by the time of her introduction and does little to show off her loner personality. Made more apparent in ''Attack,'' where one of her strongest memories is abandoning Fio on her first few missions because she was too slow.
* InSeriesNickname: "Memphis Bomb Princess".
* JapaneseDelinquents: A variation. Eri was a former ''sukeban'' (female gang leader) and she still sports blond hair.
* {{Mukokuseki}}: While she does have (light) brown eyes, her hair's a shade of blond that is anything but Asian, let alone Japanese (she's from Hiroshima). It is unknown if her blond hair was a leftover of her childhood as a ''sukeban''.
* SdrawkcabName: Spelling her name backwards in Hiragana will get the name of a famous Japanese pop star Rie Tomosaka.
* StuffBlowingUp: Starting in ''6'' her specialty is grenades.
* TomboyAndGirlyGirl: Eri's the Tomboy. Her backstory, attitude, and appearance are much tougher than Fio's.
* WeaponOfChoice: The laser.
* YoungerThanTheyLook: Eri's two years younger than Fio, considering Eri's tougher personality.
[[/folder]]

[[folder: Fiolina "Fio" Germi]]

Daughter of the massively wealthy Germi Family, hailing from Italy. The Germi family has historically been a military family, sending their oldest into service, so naturally her father wished for a healthy son to carry on the name. However, following Fio's difficult childbirth, her mother was unable to bear anymore children, making it the first time the Germi heir was female.

Eri's polar opposite, Fio was raised in a loving family, and has a cheerful and upbeat demeanor. Aside from her soldier training, she also studied chiropractics, acupuncture and moxibustion in university, and hopes to become a sports doctor in the future.

Fio's special trait from the sixth game onward is carrying extra ammo for her weapons. She starts each life with a Heavy Machine Gun, and gains 50% more ammo on weapon pickup. If playing on Easy, though, she automatically gets the Big Heavy Machine Gun as her initial armament.

!!Fio Germi Tropes:

* ActionGirl: No less a capable fighter than any of the men.
* BadassAdorable: Best exemplified by her victory animation of her falling down coquettishly. Mind you, this is after wiping out hundreds of enemy troops.
* BareYourMidriff: As is the norm with female fighters in the ''Metal Slug'' universe.
* TheChick: The medical expert of the team and also the most emotional.
* FingerPokeOfDoom: Her melee attacks include [[DualTonfas swift tonfa strikes]], [[AnAxetoGrind hatchet slices]], and [[WimpFight sissified slapping and shoving]]. Enemy soldiers die horribly all the same.
* GirlyBruiser
* GuestFighter: She is playable in ''VideoGame/TheKingOfFighters: Maximum Impact 2''.
* HeterosexualLifePartners: With Eri.
* HeroicSelfDeprecation: She usually thinks less of herself in comparison to her teammates.
* LastOfHerKind: Fio's parents' greatest fear. See StayInTheKitchen below.
* {{Meganekko}}: An archetypical example in video games. She's got the cute look, modest personality, and is overall moe because of it.
* MissFanservice: A lesser one compared to Sofia, but far better known among fans. Cute girl with with a nice figure (which is obvious on any piece of official art, especially next to the modestly endowed Eri).
* MoreDakka: Her Specialty from Metal Slug 6 onwards. The Heavy Machine Gun is basically her ''default'' weapon.
* OlderThanTheyLook: Despite her appearance and character, Fio is two years older than Eri.
* SmallGirlBigGun: The heavy weapons specialist is the smallest of the four main playable characters.
* StayInTheKitchen: Fio'a father would rather she not be in combat so damn much. Whether it's because she's a woman or because she's an only child (LastOfHerKind and thus putting the whole family line in danger since she has no children of her own) is up for debate (possibly both).
* TookALevelInBadass: She's normally the meekest of the main cast, but at the end of Metal Slug 3, she stands in a very proud manner atop of a floating Metal Slug. Eri, in comparison, has a hunched demeanor.
* TomboyAndGirlyGirl: Fio's the Girly Girl compared to Eri's Tomboy. She's got a sheltered background, [[{{Meganekko}} cuter looks]], and is much less hardened in general.
* WeaponOfChoice: The Rocket Launcher, but initially it was the Heavy Machine Gun.
[[/folder]]

!!''Metal Slug 4''

[[folder: Nadia Cassel]]

Initially, Nadia wanted to go into the modeling business, but she couldn't stop eating, which meant she kept gaining weight, so she enlisted into the Regular Army for the exercise. She soon discovered her skills as a soldier, and was chosen to help in stopping the Amadeus Syndicate from releasing its supervirus. Here, Nadia was a stand-in for Eri, who had been assigned to other duties. The one thing putting her apart from Eri is that her alternate melee weapon is a souped-up taser, capable of shredding the enemy. Unfortunately, due to some in-game bugs, she doesn't get as many points for using her melee.

!!Nadia Cassel Tropes:

* ActionGirl: Runs and guns with the best of them.
* BareYourMidriff: [[RuleOfSexy Not that it isn't a standard with the Regular Army in general]].
* BigEater: Compared to the other characters whose powerup relies in eating, she takes it UpToEleven. Her idle animation almost always leads her grabbing a bite on a chocolate bar.
* FormerlyFat: Well, except the ending has her eating a big feast alongside the other heroes.
* {{Gainaxing}}: Whenever she does her close-range attack in her Valentine's Day outfit.
* GirlyBruiser: Especially her Valentine's Day outfit in ''Defense'' and ''Attack''. [[LethalJokeCharacter This doesn't stop her from kicking ass, though.]]
* GirlishPigtails: As evidenced by the fact she joined the military not to prove herself, defeat evil, or a love of fighting, she's just a girly girl who joined for girlish reasons. Her hair is appropriately in pigtails.
* MundaneUtility: Joining the military in the midst of conflict seemed like an easier way to lose weight than eating less.
* RoseHairedSweetie: She's definitely the cutie and probably the least militaristic of the protagonists, fitting her pink hair.
* SpyCatsuit: "Special Nadia's" outfit.
* SignedUpForTheDental: Joined the military as a way to exercise and lose weight.
* SignificantGreenEyedRedhead: RoseHairedSweetie with green eyes in her portrait.
* StunGuns: She uses a taser as her melee attack.
** SetSwordsToStun: Inverted. Her taser is set to essentially killing her victims outright like the rest of the team's melee attacks.
* SuspiciouslySimilarSubstitute : To Eri, in terms of animations.
* WeightWoe: The reason she joined the military is to lose weight, going up her needs to become a supermodel. Unfortunately this gets conflicted to the fact when she's admitted to be a known BigEater.
[[/folder]]

[[folder: Trevor Spacey]]

Trevor received his first computer at age three. By the time he was seven, not only could he perform complex coding, he also worked on creating antivirus progams during summer break, many of which are still in use at the school he attended. When he ended up joining the Peregrine Falcons, he found a great deal of respect for Marco, whose own computer skills surpassed his own. Here, he acted as Tarma's stand-in. His melee involves kicking the enemy so hard, it shreds them apart; he gains double points for this, but he has to hold still.

!!Trevor Spacey Tropes:

* ArmedLegs: His melee is a powerful kick called Knife Boots.
* AsianAndNerdy: Korean and a PlayfulHacker.
* {{Bishonen}}: Compared to the other male characters, he's young and boyishly handsome.
* ChildProdigy: Literally owns and uses a computer since he was [[ImprobableAge three years old]].
* TheCracker: Zigzagged with PlayfulHacker. Becomes the Regular Army's support hacker and a sideline commando.
* NonstandardCharacterDesign: Sprites-wise, Trevor is the only male who normally has sclera around the pupil (most have BlackBeadEyes).
* ObliviousToLove: More like he doesn't know that [[CrushBlush Abigail blushes]] at the sight of him.
* PlayfulHacker: A point which causes him to get along with Marco, another playful hacker.
* TheSmartGuy: An ingenious hacker.
* SuspiciouslySimilarSubstitute : To Tarma, who was not playable in his game.
* WeaponOfChoice: The Two Machine Guns.
[[/folder]]

!!''Metal Slug Advance''

[[folder: Walter Ryan]]

Walter joined the Peregrine Falcons squad with the hopes to train his mind and body, knowing he had the stamina to keep up with the rest of them. However, he never would've guessed his initial "training" would turn out to be a rescue mission.

* FallingIntoTheCockpit: An early training mission became a very real mission as his drill instructor turned out to be TheMole.
* MamasBoy: His hobby is listed as "phoning his mama."
* PaletteSwap: To Marco.
* SuspiciouslySimilarSubstitute: Again, to Marco as the main "guy" character.
* YouGottaHaveBlueHair: His hair is literally blue. No mention is made of this.
* WeaponOfChoice: The Drop Shot.
[[/folder]]

[[folder: Tyra Elson]]

Tyra's strong desire to fight evil is what motivated her to join the Peregrine Falcons alongside Walter. After getting the highest score on the written test, she was immediately put to the physical training course on the island where the game takes place.
* BareYourMidriff: Not normal combat attire, even for a trainee.
* FallingIntoTheCockpit: An early training mission became a very real mission as her drill instructor turned out to be TheMole.
* PaletteSwap: She uses an edited version of Nadia's sprites.
* RevolversAreJustBetter: Defaults to a revolver, as shown in her official art.
* TheSmurfettePrinciple: The only female to be a member of the PF Squad. Every other female is on the SPARROW Squadron.
* SuspiciouslySimilarSubstitute: Has the same outfit as Nadia, her hair is also a red hue, and introduced as a new female character along side a new male character.
* WeaponOfChoice: The Super Grenade Launcher.
[[/folder]]

!!''Metal Slug Mobile''

[[folder:Nathalie Neo]]
A member of the Sparrows division.

* BashBrothers: Works with Ralf in games she stars in.
* WeaponOfChoice: The Super Grenade.
[[/folder]]

[[folder:Roberto Nicola]]
A member of the Peregrine Falcons.

* AscendedFanboy: Was overjoyed to work with Fio, one of his favorite soldiers.
* BashBrothers: Works with Leona in games he stars in. In ''Metal Slug Attack'', he is partnered with Fio.
* LimitBreak: The Roberto Combination, which is a set of shots from his gun and some bomb throws.
* TraumaButton: Gets overly suspicious to any beautiful woman he gets in contact with. This is because, in his first mission, he once got frozen by Beatriz posing as a helpless civilian.
[[/folder]]

[[folder:Alisa Stewart]]
A former mechanic of the Regular Army before joining as a soldier. Alisa is able to use her parachute in mid-air.

* DramaticWind: Her victory animation has Alisa removing her hand and letting the wind blow her hair out no matter the location.
* HammerspaceParachute: She can deploy as many as she pleases.
* IdenticalStranger: Her ''Metal Slug Defense'' artwork has her similarly designed as Fio.
* ImprobableWeaponUser: Uses a wrench as her melee attack.
* WeaponOfChoice: The Big Rocket Launcher.
[[/folder]]
----
!Ikari Warriors

Ralf and Clark, in between their appearances in ''VideoGame/TheKingOfFighters'' series, appeared alongside the core team for ''Metal Slug 6'', and are back for ''Metal Slug 7/XX''. Joining them in ''XX'' is Leona and later Whip and Heidern in ''Metal Slug Defense''. A better amount of information about these five can be found on their respective series' page.

[[folder: Ralf Jones]]

Aside from his participation in various fighting tournaments, little to nothing else is known about him or Clark. There's rumors flying around, but he tends to ignore them.

Though carrying half as much ammo and grenades as anyone else, Ralf makes up for this with his Vulcan Punch, capable of destroying tanks, and his melee speed is much faster than anyone else's (and his normal melee can also damage things that others cannot). He's also the only character capable of taking two hits. He's just that tough.

* DashAttack: His ''other'' special move, the Galactic Phantom Punch.
* HeterosexualLifePartners: With Clark.
* HotBlooded: The guy is willing to charge a tank with his bare hands.
* KnifeNut: Collects knives as a hobby. Though ironically he's one of the few that doesn't use them on the battlefield.
* LightningBruiser: He can run and jump as well as everyone else, has fast (and highly damaging) melee attacks, and takes 2 hits to kill, unlike most of his allies.
* MadeOfIron: Why can he take a tank shell? Just because he's that damn tough.
* OneHitPointWonder: Averted; he can take ''two'' hits. That said, certain things can still OneHitKill him, such as getting eaten by {{Man Eat|ing Plant}}ers.
* RapidFireFisticuffs: His special move, the Vulcan Punch.
* RedOniBlueOni: The red to Clark's blue.
* WeaponOfChoice: The Flame Shot.
[[/folder]]

[[folder: Clark Still]]

Clark and Ralf have been longtime friends, even in the unit the two of them are assigned to.

Clark's unique ability is his Super Argentine Backbreaker, a special melee move capable of earning him a lot of points in a short time frame. He also gains a small window of invulnerability with each enemy he tosses with this. However, it only works on certain human-sized enemies.

* CoolShades: Much like Tarma. Echoing Tarma's relationship with Marco, the shades serve to differentiate Clark and Ralf.
* DifficultButAwesome: If you can overcome its short range, the Super Argentine Backbraker will rip nearly any hoarde of (human) mooks a new one.
* HammerSpace: In ''Defense'', his special move is to pull out a large ExplodingBarrel and hurl it. In ''Attack'', his "Jet Clark" variant throws refrigerators.
* HeterosexualLifePartners: With Ralf. They've been together for years in several combat theaters.
* RedOniBlueOni: The blue to Ralf's red. He's less hot blooded and more stoic.
* TheStoic: Even when suplexing enemy soldiers, he's not exactly a ScreamingWarrior.
* StoneWall: As Jet Clark, his ability to throw refrigerators to use as blockades make him very hard to wear down.
* WrestlerInAllOfUs: His Backbreaker.
* WeaponOfChoice: The Iron Lizard.
[[/folder]]

[[folder: Leona Heidern]]

Leona was adopted by Commander Heidern following her involuntary transformation and slaughter of her hometown, and Clark and Ralf helped to oversee her training.

Leona joins the team for XX, but has to be unlocked via DLC (she's only 99 cents, well worth it). She carries an amalgamation of everyone else's skills (Stronger pistol fire, 20% more ammo and grenades, Slugs can take an extra hit, and she retains her weapons after losing a life. Interestingly, her special melee, Moon Slasher, can destroy bullets). According to her profile, Clark, Fio and Leona finished a mission that also further bonded the three as being good friends.

!!Leona Heidern's tropes:

* AllYourPowersCombined: In ''XX'', she has basically everyone else's special skills.
* AscendedExtra: Originally appeared in a cheap cell phone game before being moved to the main series.
* CatGirl: By donning cat ears, she can decrease her hit points while increasing her attack.
* CloseRangeCombatant: In ''Defense'', her moon slasher is her only move.
* GuestFighter: She originates from ''VideoGame/TheKingOfFighters'' series.
* SignatureMove: Her Moon Slasher
* TrueCompanions: With Ralf and Clark, ever since ''KOF '96.''
[[/folder]]

[[folder:Whip]]
Whip makes her debut in ''Metal Slug Defense'' as part of the ''King of Fighters'' faction. Since the ''KOF'' faction does not exist in ''Metal Slug Attack'', Whip has been moved to the P.F. faction.

!!Whip's tropes:
* CastHerd: Whip was separated from Ralf, Clark, and Leona in ''Defense'', since the latter three are part of the P.F. faction. While she eventually joined alongside them in the same faction in ''Attack'', Whip is not part of the Wrath team, rather being placed next to the Slugnoid Type-B for the Agent Sally team.
* LastEpisodeNewCharacter: Whip and Heidern were the final units implemented in ''Metal Slug Defense''.
* RevolversAreJustBetter: Her special attack is shooting a bullet from a golden revolver. Its range is short in ''Defense'' and much farther in ''Attack''.
* WhipItGood: Her standard attack. Her whip is able to cause knockback in ''Attack''.
[[/folder]]

[[folder: Heidern]]
Heidern makes his debut in ''Metal Slug Defense'' as part of the ''King of Fighters'' faction. Since the ''KOF'' faction does not exist in ''Metal Slug Attack'', Heidern has been moved to the P.F. faction.

!!Heidern's tropes
* CastHerd: Heidern was separated from Ralf, Clark, and Leona in ''Defense'', since the latter three are part of the P.F. faction. While he eventually joined alongside them in the same faction in ''Attack'', Heidern is not part of the Wrath team, rather being placed next to the Donkey Slug (Eri) for the "Operation Ikari" team.
* EarlyBirdCameo: Appeared as a drill instructor in ''Defense'''s Combat School before becoming a playable unit.
* HiredGuns: The leader of the Ikari Warriors, who sends his troops to the Regular Army whenever there's a big conflict.
* LastEpisodeNewCharacter: Whip and Heidern were the final units implemented in ''Metal Slug Defense''.
* LifeDrain: His special attack has him jump and suck the life of the closest unit.
* PrecisionFStrike: [[PunctuatedForEmphasis Go. To. HELL!]]
* RazorWind: His long-range attack.
[[/folder]]

----
!Antagonists (By faction)

!!Rebel Army

[[folder: Donald Morden]]
-->Debut: ''Metal Slug''

Morden was formerly a Vice Admiral in the Regular Army Marine Corps. Though a tough and efficient commander, he was also something of AFatherToHisMen, which greatly earned him their respect.

Things went well for Morden, up until the Central Park bombing, which not only took away his right eye (hence the eyepatch he wears), but it also killed his young son. To twist the knife even further, he later found out that Regular Army Intelligence knew about the bomb threat and pushed for the high command to stop it, but due to rampant corruption in the system at the time, the higher-ups dismissed the threat as being a mere prank or so (later blaming the bombing on a lack of intel), which, when combined with his emotional instability and rampant alcoholism following afterwards, ended in Morden's resignation.

When Morden left, all of the soldiers under his command (including Allen O'Neil) followed him out of sheer loyalty to him. This allowed him to form the Rebellion Army, and he began making swift tactical moves against the Regular Army, nearly destroying them and finally motivating them to get their act together. In fact, during his attack on the president, he gained his nickname as the "Devil Rebirth", due to just how frightening he was.

Though he was a main threat in Metal Slug, in Metal Slug 2 it turns out he teamed up with the Mars People, who gave him the technology he needed, but were quick to turn on him. He barely showed up in games 3 (where a Mars Person was impersonating him) and 4 (there were robotic duplicates of him, possibly including the one in the intro demo), and was completely absent in 5, but made a return in 6, where he, again, made a pact with the Mars People, but this time, due to the Venusians invading, it was soon under different terms. Taking a certain route in Stage 4 will mean that he's the one who actually saves the player at the end of the game.

His biggest return to the spotlight was in 7/XX, where it turns out his own soldiers, from some unspecified time in the future, went back in time to help him out, again out of sheer loyalty to him.

!!Morden's Tropes

* BigBad: For most games, though sometimes he gets the title hijacked.
* BigDamnHeroes: If you took the top path in Mission 4 in ''Metal Slug 6'', [[spoiler:he appears to save you from a great fall after the invader queen dies]].
* ButtMonkey: Appearing on screen is usually a sign that he'll suffer a HumiliationConga.
* CoolPlane: Despite being an army general, he seems to have a strong preference to copters and planes over tanks. The few times he is in a tank, its a method of defense, not hiding.
* EvilLaugh: Tends to laugh in a mocking tone upon approaching the player.
* EvilerThanThou: Frequently on the receiving end of this.
* EyepatchOfPower: The man certainly looks imposing thanks to his eyepatch.
* FinalBoss: Of the original and of ''7/XX''.
* JokerImmunity: Despite being defeated and/or double crossed whenever he appears, he always survives to lead his army again.
* MadeOfIron: When riding in the Hi-Do in the first game, he can take [[UpToEleven even more bullets]] than Allen O'Neil.
* MadeOfPlasticine: Applies to his troops.
* NotMeThisTime: Against all expectations, he is ''not'' the main villain of ''4.'' The Amadeus syndicate actually abuses this expectation, having robot copies of both Morden and Allen.
* TooDumbToLive: He allied with the Mars People a second time in ''3'' despite them betraying him in the last game. It goes as well as you'd expect.
* WellIntentionedExtremist: Distraught over the death of his son in a terrorist attack that could have been prevented and angered at corruption in the Regular Army, he abandoned the Regular Army and formed his own terrorist group, the Rebel Army, and while he plans on removing corruption from the world, his ultimate goal is to create a world wide military dictatorship.
[[/folder]]

[[folder: Allen O'Neil]]
-->Debut: ''Metal Slug''

Morden's right hand man and bodyguard. When Morden resigned from the Regular Army, Allen, alongside all of Morden's supporters, followed him out. He's most remembered for taking insane amounts of punishment and supposedly being killed each game (he's eaten by an Orca in Metal Slug 2), only to return later. In Metal Slug 3, he not only died, but came back in the same level. Aside from being nigh unkillable, he also has a wife and son to return home to at the end of the day.

He appeared in Metal Slug 4's second and final stages, whereupon fighting him at the latter reveals him to be a machine, possibly meaning you also fought a robot Allen back in Stage 2. He comes back for Metal Slug 7/XX in a Rebel Gigant, still spouting his trademark quips and insults.

!!Allen O'Neil tropes:
* ADayInTheLimeLight: He's the player character for the (Japan Only) ''Metal Slug: Allen's Battle Chronicles'' game and its enhanced American port, ''Metal Slug Mobile 3''.
* AnnoyingLaugh: When he's not taunting the player, he usually can be heard going "YAHAHAHAHAHA! YAHAHAHAHAHA!"
* {{BFG}}: Wields a large machine gun whenever he's fought.
* BossBanter:
** "C'MON, BOY!"
** "YOU'RE MINCEMEAT!"
* TheDragon: To Morden. Also doubles as TheBrute.
* DuelBoss: He almost always provides the player with a Heavy Machine Gun before his fight, to be a match against his own. In ''7'' he wield a Slug Gigant, which is matched by the player's own Gigant (though the fact that the two use the same weapon is happenstance in this case). The one time he uses a clearly advantagous weapon without giving the player something to compensate, [[spoiler:It turns out to be a duplicate.]]
* {{Engrish}}: "GO HOME TO MOMMY!"
* JokerImmunity: Like Morden, he always keeps coming back, despite having been riddled with bullets and falling to his death in the first game, the second having him fall down to the ice water but apparently getting eaten by a giant Orca. The third game doesn't have anything notable besides him collapsing and falling about twenty feet, but his body still vanishes like regular enemies do after the fight. In ''Attack'' he gets impaled by Caroline's Augensterm and ''electrocuted'' in an Extra Ops story.
* LightningBruiser: Despite being bigger than the playable characters, he's also faster than them.
* ImplacableMan: He cannot be stopped. Just shooting him alone is barely going to phase him.
* ImprobableWeaponUser: Get too close to him and he'll slap you with the ammo belt of his machine gun.
* LargeHam: He's the only character in the Metal Slug franchise to actually have spoken lines. And they are ''ALL'' taunts!
* MadeOfIron: He's a human (except in 4), just like the player characters. Unlike [[OneHitPointWonder the player characters]], he has an ''obscene'' amount of health for a human, being able to last longer than a tank!
* MirrorBoss: He's basically similar to the player character, using a Heavy Machine Gun like yours, stick grenades, and even a melee attack. The difference is that you take {{one hit|PointWonder}}, he takes ''[[MadeOfIron several]]''.
* SeeYouInHell: His death cry.
* TurnsRed: His skin turns red as he takes more damage and speeds up.
* UnexplainedRecovery: All the time. Bonus points for Metal Slug 3 having him return during the attack on the Mars Peoples' Mothership despite you apparently killing him in the same level.
[[/folder]]

[[folder: Abul Abbas]]
-->Debut: ''Metal Slug 2/X''

The leader of the Arabian forces, Abul Abbas made a joint alliance with the Rebel Army. After their defeat in mission 1, a few Arabian rebels show up in the beginning of mission 2 as a last ditch effort.

!!Abul's tropes:
* BadBoss: He has a terrible habit of refusing to own up to his own mistakes. In ''Attack'' he refuses to let his own troops stop to refuel their units, then blames them for running out of fuel at a critical moment.
* DummiedOut: Sprites of Abul attacking and setting up his white flag are present in ''2'''s [=ROM=]. These get their use in ''Defense'' and ''Attack''.
* HoistByHisOwnPetard:
** The player is able to kill Abul in ''X'' [[https://www.youtube.com/watch?v=KvVvzMGFmoM if one of Iron Nokana's shots]] [[https://www.youtube.com/watch?v=N8WF2_hQDzo lands on him]] during the [[ScoreScreen "Rescued Prisoners" screen]].
** Accusing his soldiers of laziness when they want to stop to refuel their vehicles bites him in the rear when their vehicles run out of fuel.
* IShallTauntYou: Shows up multiple times commanding his troops and taunting the player.
* KnowWhenToFoldThem: Waves a white flag once things go bad for him.
* StarterVillain: He serves as a first-level foe whose army is even worse equipped than the Rebels, and his troops lose all presence after the first level.
* TheUnfought: The player ends up fighting the mission's boss while ignoring Abul in the background.
* WhiteFlag: Raises one on his sword when he surrenders after things go south.
[[/folder]]

[[folder: Future Soldiers]]
-->Debut: ''Metal Slug 7/XX''

Morden's own troops from an unspecified time in the future. Presumably at some time after Morden was captured or killed, his own forces, again out of loyalty, gathered up their technology and, though the construction of what appeared to be a time window or portal, went back in time to help Morden out. Despite having new weapons and upgraded machinery, they still got their asses handed to them, and with their window destroyed, they were unable to do anything else.
[[/folder]]

[[folder: Allen Junior]]
-->Debut: ''Metal Slug Advance''

That's right, Allen's own son is here. He posed as a training instructor, which allowed him access to the island where the Peregrine Falcon trainees were undergoing the test. From here, he was able to lead some of Morden's forces to launch a surprise attack on the trainees, capturing the most of them and allowing Morden's troops to set up a base.

Unlike his father, though, Junior tends to act more strategically in direct confrontation against the player. However, once injured past a certain point, he eventually loses his temper and starts acting more like his father in battle. However, finding and defeating him is easier said than done.

!!Allen Junior's Tropes
* InTheBlood: He tries to act smarter than his father, and indeed becomes more successful in attacking the Regular Army than him, but in the end gives in to the same rage his father is known for.
* TheMole: He infiltrated the Regular Forces training camp by posing as a drill instructor.
* PistolWhipping: One difference from his father is that he does ''not'' typically use a knife, instead preferring to slam his opponent with his ammo belt, which is one of the few non-lethal attacks in the game.
[[/folder]]

!!Martians

[[folder: Mars People]]
-->Debut: ''Metal Slug 2/X''

Aliens from Mars, if that wasn't obvious enough (though they do resemble squids, according to some). Possessing spaceships straight out of a 50's B-movie, they allied themselves with Morden, but were really using him to weaken Earth's defenses so they could take over with little to no opposition. Though defeated at the end of 2/X, they kidnapped Morden before the events of 3, sending a Mars Person to impersonate him, and eventually capturing one of the player's characters and creating clones of him/her.

At the onset of Metal Slug 6, it appears as though they've allied with Morden again, but this time it was to find their leader, Rootmars. Unfortunately, the Invaders showed up before Rootmars could be fully extracted, and they spent the rest of the game imprisoned at the Invaders' lair, if they weren't outright killed or eaten.

Taking a certain route in Stage 5 of 7/XX will show that the Mars People are back, and at the end of the game, just as Morden's about to be taken into custody, the Mars People swoop down and take him to safety.

!! Mars People Tropes:
* AliensAreBastards: They just want to conquer and destroy without much backstory.
* AlienBlood: They bleed green.
* BrainInAJar: The Ring Laser Mecha units are operated by a brain in a jar.
* ChronicBackstabbingDisorder: They betray Morden twice, for no reason other than because they can.
* EnemyMine: They team up with both the Rebels ''and'' the Regular Army to fight an even greater threat, the Invaders.
* EverythingsSquishierWithCephalopods: Resemble giant squid or octopi.
* {{Expy}}: They look exactly like H. G. Wells' martians.
* FlyingSaucer: Their main vehicle. Some of their units are unmanned ones that fire a laser. Their mothership is an even bigger one.
* GiantSpaceFleaFromNowhere: In Metal Slug 2. Not so much in X, where they are foreshadowed better.
* HoistByHisOwnPetard: Both their betrayals of Morden and the Rebel Army lead to an EnemyMine that causes their defeat. The first time because a pilot from the Rebel Armor [[RammingAlwaysWorks rams their mothership]] and forces it to retreat, the second because the Rebel Army provides the player character with a rocket that allows them to reach their mothership.
* HomingProjectile: Martians primarily attack with three homing nuclei-like projectiles. Thankfully said projectiles are destructible.
* LastEpisodeNewCharacter: They show up in the last level of ''2''. Averted in ''X'' where they appear in earlier levels.
* OhCrap: Their standard reaction when the Invaders show up.
* RayGun: They wield these, just like classic aliens... although said guns tend to fire out slow, homing, destructible nucleus-like projectiles.
* StarfishAliens: They resemble giant jellyfish/squid. Yet they have skulls, green blood, and mouths.
* TheWorfEffect: After establishing themselves as the premier threats of ''2/X'' and ''3'', they're easily taken down, captured and imprisoned, and even ''[[FoodChainOfEvil eaten for breakfast]]'' by the Invaders in ''6''.
[[/folder]]

[[folder: Rootmars]]
-->Debut: ''Metal Slug 3''

The leader of the Mars People, he was the one who orchestrated the events of 2/X and 3. Though originally looking like a larger Mars Person (just wearing a see-through helmet), his real form was revealed after his spaceship was destroyed (and he looked an awful lot like E.T.) He was defeated at the end of 3, his brain being blown out, and sank into the ocean, presumedly dead...

... But he wasn't. At the beginning of Metal Slug 6, Morden and the Mars People were looking for his body, and just as they located it, the Invaders came in. It turns out that while he was on the ocean floor, Rootmars had apparently recovered from his freefall beating at the hands of the team, and learned his lesson as well. During Stage 4, if you take the alternate route, Rootmars will swoop down and grab your player, taking him or her to the next destination whilst also being outfitted with two gatling guns, helping take down the Venusians. Taking this route also means Rootmars saves you at the end of the game.

!! Rootmars' tropes:
* BigBad: Of ''3''.
* BigDamnHeroes: If you took the bottom path in Mission 4 in ''Metal Slug 6'', [[spoiler:he appears to save you from a great fall after the invader queen dies]].
* EldritchAbomination: He may look like E.T., but he does it Lovecraft-style.
* EnemyMine: He team up with both the Rebels ''and'' the Regular Army to fight an even greater threat, the Invaders. He even becomes playable to an extent in ''6''.
* FinalBoss: Of ''3''.
* FreeFallFight: You fight him while you and the soldier you rescued (and another player, if any) fall down to Earth.
* GoodScarsEvilScars: He has a number of Frankenstein-like stitchings on him.
* GreaterScopeVillain: He's the one who masterminded the alien invasion in ''2/X'' but was not seen in the game. You do fight his mothership, however.
* LargeAndInCharge: The normal Mars People are human-sized, he takes up most of the screen you fight him on.
* MyBrainIsBig: Bonus points for it actually being visible, encased in a dome.
* PromotedToPlayable: In Metal Slug 6's fourth stage, taking the bottom path allows you to ride Rootmars and you control both his hand and a cannon attached to his head. Using the Bomb button causes him to use his brain wave as a SmartBomb.
* PsychicPowers: Fitting for an alien with a giant brain, it has psychic powers.
* SuperIntelligence: Part of the reason he's the leader of the Mars People.
[[/folder]]

!!Ptolemaic Army

[[folder: Ptolemaic Army]]
-->Debut: ''Metal Slug 5''

This army group attacked a Regular Army base and ended up stealing a disc containing blueprint data on both Metal Slugs and Rebellion Tech, which lead to them creating their own bastardized and upgraded versions. Due to the confusing nature of the game (and the fact that so much went unused), it was hard to tell who was really in charge. It appeared as though they had gained the trust of the natives by the Corridor of Fire, and was using them to keep intruders away.

* {{Expy}}: Of the Rebel Army. Most of the enemies are even edits of Rebel soldier sprites. They're also one to the [[VideoGame/CommandAndConquer Brotherhood of Nod]].
* KnightOfCerebus: While Metal Slug 5 has most of the series usual silliness, the Ptolmaic Army's typical soldiers lack the silliness of the Rebel Army.
* PowerCopying: They specialize in stealing technical plans from the Regular and Rebel Army.
* ReligionOfEvil: They are led by Ptolmaic Shamans, and apparently worship Evil Spirit Incarnate.
[[/folder]]

[[folder: Evil Spirit Incarnate]]
-->Debut: ''Metal Slug 5''

[[quoteright:341:http://static.tvtropes.org/pmwiki/pub/images/bc04728b_1d9a_4857_9070_582cb86b8a20.jpeg]]

The FinalBoss of Metal Slug 5, a huge GrimReaper like entity that, we have no idea who this thing is. It just shows up at the end of the last stage and serves as the FinalBoss.

* AttackOfTheFiftyFootWhatever: Aside from the Mars Peoples' mothership (which is big enough to serve as an entire stage), it's easily the largest boss in the series, which is no small feat by any means.
* AutobotsRockOut: The battle against the Evil Spirit Incarnate has a heavy metal remix of the "Final Attack" theme.
* BackgroundBoss: Spends most of the fight in the background, and you have to [[AttackItsWeakPoint shoot the glowing skull on its chest.]]
* BigBad: Is presumably this for ''5'', [[GiantSpaceFleaFromNowhere but we may never know.]]
* CelestialBody: Itís entire frame seems to be made out of the fabric of space.
* DramaticThunder: Thunder and lightning strikes when the boss makes its appearance.
* EldritchAbomination: A gigantic demonic creature that [[CelestialBody looks like it was made from the fabric of space itself]]. It also has a skull in it's chest that serves as it's weak point.
* EvilIsBigger: By far the biggest boss in the franchise.
* FinalBoss: With ''5'' allegedly being the last in chronology, the Evil Spirit Incarnate serves as this for the seriesí plot, as well as the last boss for ''5'' in general.
* FlamingSkulls: The skull in itís chest seems to be burning with an ethereal or cosmic substance.
* GenericDoomsdayVillain: Even by the standards of this series.
* GiantSpaceFleaFromNowhere: Seriously? Where the hell did this thing come from? There's no explanation if it was allied with the Ptolemaic Army, or if it was their leader, or if they were a ReligionOfEvil and its their GodOfEvil they were summoning to bring about TheEndOfTheWorldAsWeKnowIt.
* HellIsThatNoise: Produces a loud screech when it shows up next to the arena.
* KnightOfCerebus: Whatever this thing is, its design is very much DarkerAndEdgier compared the usual bosses that appear in the series and is actually very menacing.
* LeanAndMean: The silhouette shows that it is a very thin being.
* NonStandardCharacterDesign: Whereas everyone else is a human, an alien or a robot, we have a towering being thatís made of space.
* PlayingWithFire: Most of its attacks will burn you to death should they kill you.
* RedEyesTakeWarning: It has a piercing gaze with red eyes.
* ScrewThisImOuttaHere: It doesn't die when defeated, it just flies away into the background.
* SinisterScythe: Which appears to be forged out of flames.
* SinisterSilhouettes: Most of the time itís pitch black, only shown off by the thunder strikes.
* WingedHumanoid: Has large, bat-like wings.
[[/folder]]

[[folder: Ptolemaios]]
-->Debut: ''Metal Slug Attack''

Originally meant to be the FinalBoss of ''Metal Slug 5'', Ptolemaios makes his true debut in ''Metal Slug Attack'' as the main villain for the "Ptolemaic Attack" event. He is the leader of the Ptolemaic Army, controlling his troops within the shadows. He uses Sol De Rokker's red jewel to create a tower for himself that attacks with lightning and rosetta stones.

A side story revolves him annihilating the Red Goblin society, with Red Goblin seeking revenge.

!!Ptolemaios tropes:
* BadFuture: Ptolemaios is implied to be the winner in a future timeline. This results in two other characters going back in time where Ptolemaios has lower amounts of power.
* BigBad: Informally in ''5''. In ''Attack'', he is this to Red Goblin.
* TheCameo: Mostly unintentional, but his towers (as well as the Stone Turtle and the Elephants) can be seen in the background of Mission 5.
* CameBackStrong: Every death he suffers results in him getting new attacks.
* DeathFromAbove: Drops Rosetta stones on top of the opposing team.
* DummiedOut: A nearly complete set of sprites is present in ''Metal Slug 5''. Most of them are given use in ''Attack''.
%%* EvilOldFolks
* HijackingCthulhu: His Abyssal form's special attack is summoning the Evil Spirit Incarnate.
* ShadowDictator: How his description in ''Attack'' [[{{Handwave}} handwaves]] his lack of appearance in ''5''.
* ShockAndAwe: The bottom of his tower produces lightning strikes.
* TheUnfought: Was intended to have a boss fight near the end of the game, but it was DummiedOut.
* WhatHappenedToTheMouse: Due to ''5'''s rushed state.
[[/folder]]

!!Invaders

[[folder: Invaders]]
-->Debut: ''Metal Slug 6''

The Mars People's nemesis, they not only appear to be physically stronger and more diverse than the Mars People, they also seemed to have better technology on their side as well. They formed the second half of Metal Slug 6's plot, especially after their first appearance was snatching up two martians and eating them.

Their queen came to Earth via an asteroid, and was quick to set up an underground shelter for her brood. After one hell of a fight against the team, she fell to her death, releasing an explosion that apparently killed the protagonists as well. Depending on which route you took in Stage 4, either Morden or Rootmars will save the player.

!!Invaders Tropes:

* AlienBlood: They bleed purple, in contrast to the Mars Peoples' green.
* AliensAreBastards: Even moreso than the Mars People.
* AlwaysABiggerFish: Right when both Morden and the Mars People have you captured, these guys then come in and make very short work of them. It even extends to the flashback where they make very short work of both the Rebel troops and Mars People.
* TheDreaded: The Mars Peoples' reaction when these guys appear is to cower in fear. [[FoodChainOfEvil And rightfully so]].
* EvilIsVisceral: They have an organic lair as opposed to the Mars Peoples' technological one.
* FoodChainOfEvil: Think the Mars People were deadly? These guys literally ''eat Mars People for breakfast''.
* GiantEnemyCrab: The Crab-tanks and Vanguards.
* KnightOfCerebus: The Mars People have an OhCrap reaction when they show up and eat them at the end of Mission 2. The final mission also has a DarkReprise of the classic "Final Attack" theme.
* HeliCritter: The Smashers, which spin their legs to fly in the air like a helicopter before inflating themselves to crash down on you.
%%* HordeOfAlienLocusts
* HorrifyingTheHorror: The Mars People who were the dangerous main antagonists of ''2/X'' and ''3'' are deathly afraid of them, cowering at first sight of the basic Invader drones.
* PuppeteerParasite: One of the Invader units is a small flying parasite-like bug that latches onto the heads of rebel troops and mind-controls them. In the final stage, a unique variant appears to have mind-controlled one of the non-selected player characters into fighting against the players.
* SpinAttack: The lowest ranking mooks move around via spindashing.
* ToServeMan: Invader Drones don't just eat Martians. Some of them can throw their neck forwards and will eat the player character whole if it connects.
* UniqueEnemy: There's a Gold Hunter Walker encountered if you take a secret path in the final mission, killing it grants 50000 points.
* ZergRush: The standard troops ambush in groups. In Mission 3, a large horde of them come spinning down from the right side.
[[/folder]]

[[folder: Invader Queen]]
-->Debut: ''Metal Slug 6''

A huge alien that serves as the final boss of 6, and the leader of the Invaders.

* BackgroundBoss: Most of the boss is in the background- you need to attack her head to damage her.
* BigBad: The leader of the Invaders in ''6''.
* DisneyVillainDeath: Falls to her death before explodes in a massive explosion.
* EyeBeams: Purple ones that aim at you.
* FinalBoss: Of ''6''.
* FlechetteStorm: Has an attack where she charges energy then releases it in crescent projectiles. Then they fly at the player from the left and right, or may even converge on them from all directions.
* HoldTheLine: The final part of the battle turns into a FreeFallFight where she's invulnerable, sending ''huge waves'' of destructible projectiles dowanwards at you.
* LargeAndInCharge: She's one of the biggest Invaders there.
* TrickBoss: You face off the pod she's encased in. It stays there, doesn't do anything, and is periodically accompanied by Venusians. When beaten, a bunch of Morden soldiers come in to celebrate with a victory music of sorts... and then her eyes light up and destroy the soldiers. Time for the ''real'' boss.
[[/folder]]

!!Others
[[folder: Amadeus Syndicate]]
-->Debut: ''Metal Slug 4''

A mysterious organization whose threat to the world was the release of the "White Baby Virus", a supervirus powerful enough to penetrate any mainframe's defenses. It also appeared as though Morden was supporting their efforts, though they had made a robotics plant at their base, creating several Morden bots, possibly including the one seen in the opening sequence.

The main man himself supposedly died at the end of the game when his base was destroyed, making him the first antagonist in the series to die for good. However, the credits sequence showed an intact computer broadcasting something.....

* TheCracker: The Amadeus Syndicate are a team of cyber-terrorists.
* EliteMooks: The disguised Amadeus troops use Heavy Machine Guns in the final level.
* EveryoneCallsHimBarkeep: Amadeus is referred to as "Doctor" in ''Metal Slug Attack''.
* EvilOldFolks: Amadeus himself
* FramingTheGuiltyParty: Their soldiers dress up as Morden's troops, and they have robot Mordens and Allens, presumably to invoke this trope. In the last level, they instead dress up as Regular Army troops.
* MechaMooks: Employ a lot of these.
* PaletteSwap: In ''Attack'', the Infantry are purple colored Rebel Soldiers.
* RobotMe: Robot Mordens and Allen O'Neils.
* SyntheticPlague: They managed to harness the Mummy and Zombie viruses from the previous games.
* VillainTeamUp: With the Rebel Army in ''Attack''. When Allen and Abigail were being ambushed by the robots, they assumed the Syndicate betrayed them. They were not; it was [[spoiler:the Syndicate's supervirus doing all the dirty work for her own.]]
[[/folder]]

[[folder: Oguma]]
-->Debut: ''Metal Slug 3D''

Pronounced Ogma, he is the head of the ridiculously massive company named after himself, Oguma was apparently funding Morden's efforts, but was actually using him to help find a recording device deep underground, the Alator. It turns out that Oguma was one of few survivors of a long-extinct race, the Tuaha de Dunan, who were shown to be technically advanced.

His culture was said to self-destruct at the peak of their evolution; to combat this, they placed a recording device on a planet, then hibernated for 300 million years. If the information gathered by the device clashes with them, they simply erase the world's history and start over, which has possibly caused some time-space problems.

Near the end of the game, after betraying Morden, he used the Alator to release the Lugas, which then absorbs the information from Alator and begins its mission to erase history, prompting the crew to stop it. When Lugas was absorbed by a previous experiment, the Luu (and beaten by the crew afterwards), it goes crazy as Oguma and his followers stay behind in an attempt to further stop it, despite Marco's protests.

At the game's end, as Rumi is about to head out, Oguma shows up out of nowhere and hands her his information disc before leaving, hoping the people would learn from his prior mistakes.

!! Oguma Tropes:
* AbusivePrecursors: Oguma and his people essentially began life on Earth, but they have no problem snuffing it out in pursuit of their goals.
* AffablyEvil: Speaks in a very polite and calm voice.
%%* AntiVillain
%%* KnightTemplar
* ShoutOut: The Tuaha de Dunan are named for the pantheon of [[Myth/CelticMythology Celtic myth]].
* TheStarscream: Betrays Morden halfway through the game after showing his true colors, and eventually becomes the game's BigBad.
%%* SufficientlyAdvancedAlien
%%* WellIntentionedExtremist
[[/folder]]

[[folder: Pharaoh's Arc and the Mummy Army]]
-->Debut: ''Metal Slug Attack''

An expansion of the mummy enemies, the Pharaoh, Mummy Warrior, and Mummy Cat make their first appearance in the "Mummy's" event.

!!Tropes for all three characters:
* ActuallyFourMooks: Subverted. While the Pharaoh's Arc consists of multiple mummies on a chariot, they are all part of the same unit.
* DistractedByTheSexy: The Mummy Cats' main way of luring their enemies.
* DubNameChange: The Mummy Cats are called Sexy Mummies in Japan.
* EnemySummoner: The Mummy Cat's attack is to summon mummies that spit out poison bombs. If her third skill is unlocked, enemies hit by them have a chance to be stunned.
* KillItWithFire: The Mummy Warrior uses a long torch as his weapon.
* PaletteSwap: The Lovely Mummy is a red colored version of the Mummy Cat.
* SupportPartyMember: The Mummy Cat is awkward to use, but three of her four skills involve increasing the strength of Mummies, Mummy Warriors, and Mummy Dogs.
* VillainousBreakdown: The Pharaoh turns green in rage alongside his minions after being defeated. As the Tyrant Pharaoh, he starts commanding in a furious manner.
[[/folder]]

----
!Support Characters and other notable NPC's

[[folder: Rumi and Madoka Aikawa]]

Rumi originally joined the Regular Army to make use of their medicinal facilities to help her ailing mother, who had a weak heart, and her sister Madoka, who was physically ill. Due to a paperwork SNAFU, she was shipped to the front lines, and despite having never completed her training, she made it back unscathed, a miracle in and of itself.

She was offered the chance to leave and live life as a civilian, but she declined the offer, and was soon transferred to the Supply Division. Before each mission, she fills her backpack with various supplies, and treks out to deliver the goods to Regular Army Soldiers... but there's one problem. She's horrible with directions, and is likely to wander off and be found in a completely different location, earning her the nickname "The Wandering Ghost" by most soldiers. She later found out her sister Madoka also joined to become more physically fit, and was also placed in the Supply Division... and shares the same atrocious sense of direction her sister has.

Though mostly a background character in the main games, Rumi was given a bigger role in Metal Slug 3D, giving information to Marco and even allowing access to a Garage where the player could customize their own Metal Slug vehicle.

!!Rumi and Madoka tropes:

* ActionGirl:
** Promotional art for ''Metal Slug Defense'' shows Madoka parachuting while operating a bazooka. She is not a unit in ''Defense'' but she is in ''Attack'', using her bazooka from her backpack and throwing a medicine item to heal units.
** Rumi [[PromotedToPlayable turns into one]] in ''Metal Slug Attack''. She throws grenades from her backpack to her foes and tosses support items to her allies. Madoka gets added later, packing a Bazooka with great range and a humongous rate of fire and healing the front line.
* BewareTheNiceOnes: These two have some obscenely powerful Normal attacks in ''Attack''.
* ButtMonkey: A minor one, tagging either one of the sisters will cause them to fall to the floor and shooting them from the back tears their backpack open, dropping various items. The former also occurs when the player taps on Rumi on both tower defense games.
* CombatMedic: Madoka's special in ''Attack'' heals friendly troops.
* TheChick: Compared to Fio, Rumi is not willing to fight (and never wanted to do so in the first place), but Rumi is nice enough to help her fellow allies whenever she can.
* CuteClumsyGirl: Given the above. It's taken even further in ''3D'' when Rumi tries a dynamic entrance from a helicopter and screws it up.
* FanservicePack: Apparently, they've been starting to unbutton their shirts since ''Defense'', even though their sprites in ''Attack'' show them with their shirts buttoned all the way up.
* InSeriesNickname: "The Wandering Ghost"
* ItRunsInTheFamily: Both sisters being terrible with directions.
* TheMedic: Rumi is seen in the bad ending of ''Metal Slug 4'' taking care of the characters who got caught in the final mission's explosion. The Recovery Support in ''Metal Slug Attack'' represents her in a nurse outfit. She later turns into a CombatMedic in the 2.3.0 update. In the 2.5.0 update, Madoka is literally this, as her special attack heals the players units on the map.
* MotorMouth: In ''3D'', Rumi is very talkative, cheeky, and prone to going on tangents. She even sasses Marco after he gives her direct orders (she's a corporal; he far outranks her at Major).
* {{Mukokuseki}}: Let's be honest, they look even less Japanese than Eri.
* NoSenseOfDirection: Though they count as P.O.W.s, they are never caught by the enemy. They just happened to wander through the area.
* OlderThanTheyLook: Despite being a PaletteSwap, Madoka is eleven years older than Rumi.
* OutOfFocus: Rumi has had more game appearances and cameos than Madoka. In both tower defense games, Rumi is the one who generates AP in the field and gets playable status in ''Attack''. In ''Attack'' only, Madoka appears in the item support menu, but now appears as a playable unit alongside her sister in the 2.5.0 update.
* PaletteSwap: Madoka has brown hair and grey attire compared to Rumi's blonde hair and green attire.
* PintSizedPowerhouse: Both walk and carry an overly large backpack holding various ammunition and food items. Downplayed as they seem to be struggling to keep balance.
* SeriesContinuityError: ''Metal Slug 3D'' has Rumi ranked as a Corporal even though she's a Sergeant in every game she appears in.
* StunGuns: Madoka's close range attack in ''Attack''.
* TimedMission: If they are on screen long enough without being tagged, they will stop to salute and run away, not giving any credit to the player for rescuing them.
* UnusuallyUninterestingSight: Both sisters tend to wander the active battlefield without any care. It is not until they see one of the protagonists where they bail out of there.
* WimpFight: One-sided in ''Attack'', Rumi flails her hands rapidly if anyone gets close to her; [[FingerPokeOfDoom it's still enough to knock them out]].

[[/folder]]

[[folder: Hyakutaro Ichimonji]]

A Second Lieutenant of the Regular Army, he's a living legend among the soldiers. Pretending to be a captured POW, once he's "rescued" by the player, he helps out by firing homing Hadokens at the enemies and spin-kicking anyone else who gets too close. He will flee if you die, though.

!!Hyakutaro Ichimonji tropes:

* GuideDangIt: Sometimes appears when the player hits a specific invisible spot multiple times.
* KamehameHadouken: His main attack has him fire a ''homing'' hadouken at enemies. It also deals pretty good damage too.
* ObfuscatingStupidity: He pretends to be a captured POW ''on purpose''. Once he's "rescued", however...
* ScrewThisImOuttaHere: Runs away once his rescuer dies.
* ShoutOut: [[Series/KamenRider His first name starts with the letter H, and his last name is Ichimonji]], [[NamesTheSame but he's no Hayato]]. Doesn't stop him from kicking ass though.
[[/folder]]

[[folder: Utan]]

An Israeli orangutan that wears a diaper and carries an Uzi.

!! Utan Tropes:

* BadassNormal: Compared to the main characters.
%%* EverythingsBetterWithMonkeys
* GagPenis: If you look at his IdleAnimation close enough, you'll notice he pulls out 3 bananas out of his diaper and eats them, after which he tries it again but pulls out his [[IncrediblyLamePun monkey dong]] instead, blushes and quickly stuffs it back inside.
* StockAnimalDiet: As a monkey, he eats bananas.
[[/folder]]
-----

! Combat School Instructors

[[folder: Sophia Greenville]]

The drill instructor from ''Metal Slug 1'' (Neo Geo CD and PSX).

!! Sophia Tropes:

* AscendedExtra: While every instructor in the series shows up in ''Metal Slug Defense'', Sophia is the only one that hosts the Combat School in ''Attack'' (along with new sprites for her).
* BabiesEverAfter: Margaret, the instructor from Metal Slug X hints that Sophia retires to raise a family.
* TheBusCameBack: Shows up with Margaret in the second and third Pachislot games in Japan. In the West, it is in ''Metal Slug Defense''.
* MsFanservice: There's a good amount of art dedicated to her in the art galleries of the home versions.
* PassionateSportsGirl: What made her easily excel as a member of the Peregrine Falcons. Her favorite sport is Basketball, and also dabbles in bass fishing.
[[/folder]]

[[folder: Margaret Southwood]]

The drill instructor of ''Metal Slug X'' and Gimlet's mission control in ''Metal Slug: Second Mission''.

!! Margaret Tropes:

* AscendedExtra: Unlike other instructors, she has given larger roles in certain games. In ''Second Mission'', she appears as mission control in the main adventure and even shows up in certain missions as the end goal. In ''Defense'', she hosts the game's events.
* ArtShift: ''Metal Slug Defense'' uses her sprites in ''X'' for the Events and her new artwork for the Combat School.
* DrillSergeantNasty: A jerk to you on the lower ranks, although she'll soften up as you rise among the ladder.
* EarlyInstallmentCharacterDesignDifference: Wore a green military dress in ''X'' before changing to a blue dress for ''Second Mission'' onward.
* EasterEgg: [[spoiler:Touching her breasts]] in ''Metal Slug Defense'' will cause her to react depending what rank you are in.
* EyesAlwaysShut: [[OOCIsSeriousBusiness If she opens them]], you've either impressed her, or you've made a complete ass of yourself.
* HairColorDissonance: It's uncertain if her hair is blonde or lightish brown but sometimes her hair is represented by a darker shade of brown.
* LikeAGodToMe: Hitting the Super Devil rank will make her admire you to the point of calling you "Her Majesty".
[[/folder]]

[[folder: Riviera "Lilly" von Wittenberg]]

One of the two drill instructors in ''Metal Slug 6''.

!! Lilly tropes:
* DrillSergeantNasty: Even moreso than the other instructors.
* FanservicePack: Shows more cleavage in ''Defense''.
* HairDecorations: Has a feather on her head.
* HairTriggerTemper: Most of the time looks calm until something provokes her.
* QuitYourWhining: Hates whiners and is often cold with them.
[[/folder]]

[[folder: Maryell "Mary" von Wittenberg]]

One of the two drill instructors in ''Metal Slug 6''.

!! Mary tropes:
* DrillSergeantNasty: Averted, she's much nicer and less stern than the other instructors.
* TheKlutz: Seen dropping her documents.
%%* YouGottaHaveBlueHair
[[/folder]]
-----

!The Slugs

[[folder: SV-001]]
The first Slug in the series, and the titular Metal Slug. Capable of shooting a vulcan machinegun 360 degrees and a low-velocity round forwards but incapable of turning around, and has a reduced jump. Variations include:
* The Type-R, which sacrifices power for maneuverability.
* The Experimental, which sacrifices maneuverability for power.
* The Type-B, which is stronger in all areas, the Bronze, which is never used by the player.
* [=SV-000=] and the Proto 2, a less defensive prototype that is able to turn around.
* The Black Hound, a Ptolemaic-made variation the is remotely controlled and equipped with a laser and homing missiles.
* MS-Alice, an SV-001 inhabited by a sentient A.I. named Alice; created by Marco.

!!SV-001 Tropes
* AIIsACrapshoot:
** The Black Hound's an AI-controlled tank that goes rampant, attacking/killing its own Ptolemiac allies in the area before you face it.
** Averted with [=MS-Alice=], who is completely loyal to Marco for creating her.
* ArmoredCoffins: There's no way to easily bail out of the 000. Either you get out after defeating all enemies or letting it explode.
* ArmorPiercingAttack: Any of them can acquire Armor Piercing Shells, which do extra damage against enemy tanks, and, most importantly, fly all the was across the screen and are spammable.
* AllYourPowersCombined: The Type-B has the positive traits of the Experimental and the Type-R
* BackwardsFiringGun: The SV-001 Type-R in the first level of the third game has the unique property of firing in the direction opposite the player points. This is important, since the first boss is spent frantically running away from it.
* BonusBoss: Fighting the Black Hound is entirely optional in a secret area, and it gives no reward.
* DiscardAndDraw: As an enemy, the Black Hound is capable of ramming, firing its main cannon, a laser, a mortar attack, and its own machinegun. As a playable unit in ''Advance'', it retains its capability to ram enemies and fire its main cannon, but lacks the laser, mortar and machinegun. Instead, it has the ability to spam homing missiles.
* EscapePod: They are equipped with a floatation device, which is buoyant enough that the player can survive falling from ''space'' with it.
* HomingProjectile: The Black Hound uses this when it becomes playable in ''Advance''. [[MacrossMissileMassacre A rapid fire version of it, too]].
* MiniBoss: The Black Hound first appears as an optional boss in ''5'' before becoming playable in ''Advance.''
* MightyGlacier: They all take two to five hits to the player's one. However, their overall slower speed and lower jump height also makes dodging harder.
* PromotedToPlayable: In ''Metal Slug Advance'', finding the Black Hound's card will allow the player to use it. Unlike its encounter in ''5'', it primarily uses homing missile spam.
* RedOnesGoFaster: The Type-R is orange.
* SuperPrototype: Ad advantage the 000 has over the 001 is the ability to turn around fairly easily. Unfortunately, the exit hatch is easily warped, making the thing into a deathtrap if it gets hit at all.
* SuicideAttack: Pressing Fire and Jump while in it will cause it to rush forward and explode.
[[/folder]]

[[folder: Slugnoid]]
A sideways-walking, high-jumping slug designed for mountainous terrain. First appears in ''2'' and has had consistent appearances since. It is equipped with two Vulcan Cannons, as well as a third, downward facing cannon, whose ammo varies depending on the game. The standard Slugnoid and the higher-grade blue-tinted Type-B use Flame ammo, which spreads in all directions when hitting a surface, while the Walker Slugnoid and the deep-red Slugnoid Type-R fire Fat Lizards. The Type-B features even greater jump height.

!! Slugnoid tropes
* ActionBomb: The Fat Lizard ammo, used by the Walker Slugnoid and the Type-R, which is a small ball with legs that runs to the left of the player, then explodes.
* BreakableWeapons: It loses its cannons when damaged. After taking two hits, it's left without any vulcans.
* [[ThisLooksLikeAJobForAquaman This Looks like a Job for Slugnoid]]: It's only ever really able to shine in situations that require more vertical movement than horizontal. In ''2,'', the fact that its missile travel ''downward'' means its only really useful when an enemy is directly below you. It appears to be designed with fighting the second boss of ''2'', its first appearance, in mind.
* GlassCannon: While its firepower is stronger than the Slugnoid, it's very cumbersome to use, making it hard to keep it around. In comparison to other Slugs and the players it's still a mighty glacier.
* InASingleBound: The Slugnoid's specialty, which is improved even more for the Slugnoid Type-B.
* JumpJetpack: Its high jumps are jetpack-assisted.
* MolotovCocktail: Certain versions of the Slugnoid have an incendiary bomb as their bomb ammo, setting the floor underneath on fire.
* MoreDakka: It has ''two'' cannons as opposed to one.
* {{Nerf}}: ''X'' makes some levels harder by replacing the SV-001 with the more awkward Slugnoid.
* RedOnesGoFaster: The Type-R, but it's still not as fast as even the SV-001 Experimental.
* ShowsDamage: Taking damage causes the Slugnoid to lose a gun.
* WalkingTank: It's on two short, if stubby, legs.
[[/folder]]

[[folder: SV-Camel]]
A camel equipped with one or two Vulcan Cannons. First appearing in ''2'' to assist the player during the first Arabian levels, it leaves the player during the second. After returning when the protagonists return to the desert in ''3'', it remained absent from the series until ''Defense.'' It is notable for being the first animal Slug in the series. it does not carry its own bombs, so the player instead throws their own grenades while on the camel.

!! SV-Camel tropes
* [[AutomatonHorse Automaton Camel]]: Averted in one instance. After the first level of ''2'' or ''X'', it will neglect to follow the protagonist, to remain near a water source. Otherwise, it is incapable of being hurt.
* DenialOfDiagonalAttack: While its cannon can fire in all directions, it can't turn around. So you will only be able to throw grenades forward while on it.
* FragileSpeedster: Faster than the other tanks, and faster than the player when runnning. However, outside of elevating the player above low-ground attacks, it offers no protection.
* LovableCoward: It refuses to follow the protagonists into an ancient tomb, or into an army of man-eating plants, but is invincible when you do have it.
* TruthInTelevision: Camel-mounted machine guns actually existed in real life, called ''zamburaks''.
* WeaponizedAnimal: A camel with a rapid-fire zamburak attached to its side.
[[/folder]]

[[folder: Slug Flyer]]
A tiny jet first appearing in ''2'', and every game except ''4'' since. It's equipped with two 10mm cannons which can fire 30 degrees above or below it, as well as Sidewinder missiles that fire directly forward. It's only variation is the Slug Jet, which is controlled by an NPC instead.

!! Slug Flyer tropes

* CoolPlane: It's a hilariously small aircraft that functions just as well as a normal one, and comes with a rapid gun and missiles to boot.
* DavidVsGoliath: The fight between Slug Flyer (if you chose it) and the Dragon Nosuke has the Flyer smaller than the Dragon Nosuke's "head". The fight between Slug Flyer and Shooting Ray in ''5'' shows that the Flyer is barely the size of a single engine of the Shooting Ray.
* HomingProjectile: Its missiles orient themselves slightly on their own.
* JetPack: Starting in ''3'', many of them contain a jetpack and goggles for the player, for if the Flyer gets destroyed.
* ThisLooksLikeAJobForAquaman: It's usually only available when enemy planes are about, an exception being ''2/X'' where it can be used against the Dragon Nosuke.
* UnexpectedShmupLevel: Tends to appear in several ShootEmUp-like segments of the games.
[[/folder]]

[[folder: Elephant Slug]]
A weaponized elephant found in a Sasquatch cave in ''3.'' After freeing it from a tomb of ice, the player can ride to gain an advantage against invading zombies, who have slaughtered the native Sasquatches. It is capable of shooting electricity and fire from its trunk.

!! Elephant Slug tropes
* FireBreathingDiner: To gain the ability to shoot fireballs, it must pick up a hot pepper.
* LightningFireJuxtaposition: The two MutuallyExclusivePowerups that are unique to it are a hot pepper that gives it the ability to shoot fireballs, or a car battery that grants it the ability to shoot a lightning beam.
* MightyGlacier: While it does not technically offer any protection, it is so tall that almost no zombies that are on the same floor as the player can hit them. Meanwhile, it can't jump is as slow as molasses.
* ShaggyDogStory: It starts to help you after you free it from the ice its trapped in. In the end, the player either abandons it among the zombies or leaves it trapped in another pool of ice.
* ShockAndAwe: It can breathe electricity if it eats a car battery.
* TrampledUnderfoot: It can kill a zombie merely by walking over it.
* WeaponizedAnimal: An elephant with a gun attachment to it. It can even eat peppers or batteries for it to use fire or electrical attacks!
[[/folder]]

[[folder: Slug Mariner]]
A small one-seater sub with a high mass Vulcan and torpedoes that sink to the floor, which appears in ''3'' and ''5''. A variation, the Slug Sub, is capable of anti-air combat and has an additional supply of depth charges.

!! Slug Mariner tropes

* CaveBehindTheFalls: One inexplicably holds two Mariners in the third stage of ''3''.
* InertiaIsACruelMistress: It uses high-mass rounds, giving it serious difficulty when shooting from below
* ShoutOut: The Slug Sub is a direct recreation from the submarine from ''VideoGame/InTheHunt'', while the Slug Mariner is essentially a chibi ''Thunderbird 4'' from ''{{Series/Thunderbirds}}''.
* SuperPrototype: The Slug Sub is actually the ''prototype'' of the Slug Mariner, despite its more diverse moveset.
[[/folder]]

[[folder: Ostrich Slug]]
A weaponized ostrich found in Rebel territory in ''3''. It's capable of running fast, jumping high, and is equipped with a machine gun.

* DenialOfDiagonalAttack: While its cannon can fire in all directions, it can't turn around. So you will only be able to throw grenades forward while on it.
* FragileSpeedster: Faster than the other tanks, and faster than the player when runnning. However, outside of elevating the player above low-ground attacks, it offers no protection.
* WeaponizedAnimal: An ostrich with a rapid-fire gun attached to its side.
[[/folder]]

[[folder:LV-Armor]]
This mech is the Rebel Army's version of the "Slugnoid" and shares features like its ability to jump and even can use a jetpack of sorts. Unlike most slugs, you can also pick up weapon crates to equip it. It stabs nearby enemies with claws and fires shell from its arm cannon.

* ArmCannon: It fires its equipped weaponry from them.
* DoubleJump: It's capable of using a JumpJetPack if it jumps in midair.
* ExclusiveEnemyEquipment: Averted, you're able to hijack them after killing their pilots.
* HandBlast: It appears to fire its weaponry from its palms/claws.
* JumpJetpack: Its double jump is jetpack-assisted.
* MechanicallyUnusualFighter: Out of all the slugs, its ammunition is limited and it can change its weapons depending on the ammo crates you pick up.
* SnipingTheCockpit: Their defeat animation as the rebel soldier within get killed. If you lack a slug, it'll become rideable, otherwise it explodes.
[[/folder]]

[[folder: Bradley Slug]]
A Regular Army variant of the common rebel M15 Bradley, that was stolen from the Regular Army.

!! Bradley Slug tropes

* CutscenePowerToTheMax: Jumping into it for the first times has the player turn the Bradley Slug around to face the correct direction, something that would be incredibly useful to do in game but is impossible for the player to do.
* GoodColorsEvilColors: Bright Green to represent the Regular Army, as opposed to the grey/dark green of the bad guys.
* GlassCannon: It houses one of the most powerful secondary fires available, but is very fragile.
* HowDoIShotWeb: Despite being found in the hands of rebels, they don't have any idea how to work its vulcan cannon or its jumping ability, only knowing how to operate its indirect missile fire like their standard Bradleys.
* JumpJetpack: Is jumps with the help of a thruster beneath its treads.
* MercyInvincibility: Subverted. It receives no invincibility and can even be hit multiple times with the same bullet.
[[/folder]]

[[folder: Slug Gunner/Armor]]
The SVW-001 Slug Gunner and its variants are considered the final evolution of Metal Slugs. Walking on two legs for mobility, or on treads for speed, this type has the highest firepower but lowest speed of common slug types. Variants include the Proto Gunner, which is an quicker, unarmored version, and a multitude of mask-differentiated enemy variants. It is based on the rebel-designed LV Armor, which itself has variant branches of design in the more compact Slug Armor and the mass produced Ptolemaic Unit. The Ptolemaic Unit itself has four variants: Armor, Claw, Gunner, and [=MG=] (Machine Gun).

* AmbidextrousSprite: The Slug Gunner swaps its weapons while turning.
* AwesomeButImpractical: The LV Armor, unlike other slugs, requires ammo, can't shoot diagonally (some of them can do the heavy machine gun spreading motion), and takes one full second to jump makes it a liability at the worst of times.
* CloseRangeCombatant: The Ptolemaic Claw Unit is the only Armor to not have any projectiles at all, only using its fists. Conversely, the [=MG=] has only guns and no ability to melee.
* DenialOfDiagonalAttacK: The LV Armor has a major deficiency in its ability to shoot diagonally, which even applies to heavy machine gun ammo.
* DoubleJump: Most kinds can use rockets to boost itself once in the air.
* GatlingGood: One of the Slug Gunner's arm is equipped with a gatling gun.
* MiniMecha: They are mechas as large as the slug units.
* TransformingMecha: The [=SVW-001=] can morph between a Tank and a Mecha.
* PileBunker: The Slug Gunner has a pile bunker powered by revolving chamber.
* SuperPrototype: For those who prefer speed over mobility, the Proto Gunner is actually better.
[[/folder]]
-----

!Bosses

[[folder:In general]]
* EvilIsBigger: Pretty much all of them dwarf the size of you and your slug, the only exception being the Rebel Gigant (who's the same size as your Slug).
* VehicularAssault: Most of the bosses are a huge vehicle or robot of sorts that the player has to fight on foot or in a Slug.
[[/folder]]

!!''Metal Slug''
[[folder:Tetsuyuki]]
The first boss of the game and series, the Tetsuyuki is a flying warship created by the rebels for combat, equipped with heavy armor and weapons. One of these crash-landed onto the Villeneuve Mt. System, where it was fortified by the rebels to serve as a base of operations. Some of its weapons are still operational.

* CoolPlane: Albeit one that doesn't fly.
* StationaryBoss: Doesn't move from its spot, due to having crash-landed and made into a stationary base of operations.
* WarmUpBoss: All its attacks are relatively easy to avoid.
* WaveMotionGun: It can charge up with one of these and fire. Either crouch or stay on higher ground to avoid it.
[[/folder]]

[[folder:Hairbuster Riberts]]
Designed to be a heavy bomber aircraft, the Hairbuster Riberts comes equipped with several forms of armaments, such as guided missiles and bouncing bombs, making it a versatile weapons platform capable of quickly adjusting to the situation. More than a hundred of these aircraft were produced, all in their testing stage.

* BossArenaIdiocy: Of all the places it could fight you in, there just had to be three rising platforms that gave you ample cover from most of its attacks.
* CoolPlane: Unlike the Tetsuyuki, this one does fly.
* RecurringBoss: It also appears in ''Metal Slug 3'' as one of the minibosses in the final level. Allen pilots it this time.
* TraintopBattle: Its encounter in ''Metal Slug 1'' has you battle it on a moving train.
* VillainExitStageLeft: In ''Metal Slug 1'', Morden's in the aircraft. When destroyed, he drops out of it, but a Rebel in a Flying Tara rescues him and exits the area.
[[/folder]]

[[folder:Tani Oh]]
The Tani Oh is a prototype heavy artillery tank, armed with two huge cannon capable of devastating large areas without much effort: these twin guns are possibly an experimental railgun, since their shots are instantaneous light bolts and the turret, instead of ejecting the expanded casings, discharges smoke and heat from the vents on its back. It is also equipped with two turrets on each side, both with a minigun and a mine launcher, to cover the tank in short range. Only one unit was produced, being used by the Rebels for testing purposes in the Käthehirt Valley.

* LandMineGoesClick: Its side launchers can fire landmines.
* MeaningfulName: Tani Oh means Valley King in Japanese. Appropriately enough you encounter it at the top of a valley.
* SamusIsAGirl: Not the tank itself, but its pilot. In the Metal Slug pachinko game, it's revealed that its pilot is a blonde woman named Letta.
* TankGoodness: A huge Rebel army tank with a laser cannon/railgun type weapon and mine launchers.
* WaveMotionGun: The main cannons fire some sort of laser or railgun type weapon that hits anything in its range instantly.
[[/folder]]

[[folder:Shoe & Karn]]
Shoe & Karn are a pair of massive tanks that together make up the fourth boss in Metal Slug: Super Vehicle-001. They are each armed with one main turret-mounted cannon, two sub-cannon turrets on the front, and a missile launcher on the back. Two side-mounted hatches allow soldiers to help defend the tank as well, usually with bazookas or rocket launchers.

* DegradedBoss: After fighting them as a boss, the following level has you fight a miniboss version of Shoe as it advances towards you from behind. You also have to fight Shoe as a miniboss in Mission 5 of ''X''.
* DualBoss: You fight both of them at the same time.
* MiniBoss: Shoe is encountered as one in Mission 5 of both the original game and ''X''.
* TankGoodness: Two large Rebel army tanks with fireball cannons and missile launchers.
[[/folder]]

[[folder:Iron Nokana]]
The Iron Nokana is a modified giant armored truck that was adapted for combat. Its firepower is concentrated on the front, with a cannon and rocket launcher turret on the top and a hidden flamethrower on its bottom. To compensate for the lack of firepower in the rear, a Girida-O is mounted on its back.

* FireBreathingWeapon: Carries a hidden flamethrower on its bottom.
* MacrossMissileMassacre: Its carries a multi-missile turret on top.
* RecurringBoss: Appears as the first boss of ''Metal Slug X''.
* TankGoodness: Carries a Girida-O tank on its back to serve as its rear firepower.
* WeaponizedCar: It's a weaponized truck.
[[/folder]]

[[folder:Hi-Do]]
The Hi-Do is a gunship helicopter used by Donald Morden. Designed for testing purposes, it has heavy armor and is equipped with several weapons, making it a versatile combat vessel.

* DestructibleProjectiles: Both its bombs and missiles can be destroyed. A ''very'' good thing too, since it would be nearly impossible to avoid some of its attacks otherwise.
* DeathFromAbove: It's capable of using a carpet bombing attack where it drops bombs all over the area.
* FinalBoss: The last battle of ''Metal Slug 1'', where Donald Morden himself pilots this.
* HomingProjectile: Its missile attack will home in on the player.
* MacrossMissileMassacre: Has a missile launcher on its front that shoots a swarm of homing missiles.
[[/folder]]

!!''Metal Slug 2/X''
[[folder:The Keesi]]
The Keesi is a VTOL gunship meant to provide close air support to ground troops. It is equipped with anti-air guns on its wings and can drop heavy bombs (these weapons are not used in-game), and its size is enough to carry support tanks on its wings. The Keesi is also capable of using its jet engines to burn anything underneath it.

* DemotedToExtra: In ''Metal Slug X'', it's replaced by the Iron Nokana as the first boss, and is instead relegated to the miniboss of the third mission.
* CarFu: In ''Metal Slug X'', it drops tanks on you as an attack.
* CoolPlane: A large gunship with anti-air guns and can carry troops.
* ClownCarBase: In ''Metal Slug X'', it can carry an unlimited number of tanks on its wings, and replenishes them after it drops them.
* FlunkyBoss: In ''2'', it will spawn Arab soldiers to attack you. Subverted by the bazooka soldiers that assist it once its health gets low, they cannot be damaged in any way.
* RecurringBoss: It appears as a miniboss in ''Metal Slug X''.
* TankGoodness: It's capable of carrying tanks on its wings, and they do attack with their cannons.
* WeaponizedExhaust: One of its more dangerous attacks is to fire hot exhaust from its jet engines, then sweep the area by moving left and right.
[[/folder]]

[[folder:Aeshi Nero]]
The Aeshi Nero is a gigantic excavator resembling a cobra. Designed to travel through the underground, it is used by the rebels. Although it's primarily designed for digging tunnels, it can be re-purposed for combat in a pinch.

* AstonishinglyAppropriateAppearance: It's a mech that happens to resemble a cobra and also happens to be fought in an ancient Egyptian pyramid. Cobras were one of the animals worshiped by the ancient Egyptians.
* MechanicalMonster: A giant excavator resembling a cobra that tries to "swallow" the pillar you're on.
* MacrossMissileMassacre: Can fire out a slew of homing missiles.
* PlatformBattle: The player has to jump from platform to platform as it chases them up the large pillar.
* ReptilesAreAbhorrent: It's a giant cobra excavator mech that's hell-bent on "eating" the player characters.
* RiseToTheChallenge: It'll charge upwards now and then, and as such the player needs to move upwards as well to avoid electrical death.
* WaveMotionGun: Charges up a large purple laser that hits the entire middle of the area.
[[/folder]]

[[folder:Dragon Nosuke]]
The Dragon Nosuke is a quadruped tank, designed to protect the Rebel Supply Train with its gatling gun and flamethrower. The tank is also equipped with hydraulics within its legs, allowing it to crouch - crushing anyone or anything that happens to be beneath it.

* SpiderTank: A tank with four "legs" that allow it to walk or crouch.
* FireBreathingWeapon: Its underside carries a flamethrower.
* FlunkyBoss: It's capable of spawning helicopter firebombs that home in on you and can be destroyed.
* GatlingGood: Comes equipped with a gatling gun that can fire either small or large bullets.
* GroundPound: If the player tries to be sneaky by hiding under its legs to avoid its gunfire, it will "sit down" on the platform and crush them instead.
* OneHitKill: Getting crushed by it will destroy your Slug [[ArmoredCoffins and you]] instantly.
[[/folder]]

[[folder:Big Shiee]]
Big Shiee is a large amphibious tank, designed for traveling on water and land, using its tracks to travel like a conventional tank. It is armed with several 75mm APDS cannons, as well as a large main cannon which is hidden on the front. It literally serves as a land battleship.

* BackgroundBoss: It attacks the player from the background, never once entering the foreground or the same plane as the player.
* {{BFG}}: Once its health gets low enough, it'll open up and reveal a HUGE cannon that fires large exploding bullets. This is incidentally also its weakpoint.
* MilitaryMashupMachine: It's essentially a land battleship on tank treads.
* RocketJump: Surprisingly, you're able to use the explosions from its {{BFG}} to boost yourself and get a better shot at it.
* TacticalSuicideBoss: If it didn't open itself up to expose its huge cannon, it would be functionally invincible.
* TankGoodness: A cross between a battleship and a tank.
[[/folder]]

[[folder:Hozmi]]
The Hozmi is a nuclear-powered submarine, designed for naval battles. It is equipped with a powerful electric cannons with long range. It is possible that the Hozmi could be constructed with alien technology.

* AbandonShip: When defeated, Rebel soldiers can be seen jumping out of it and into the sewer water.
* DownTheDrain: It's fought in a sewer, for some reason.
* {{Expy}}: Of Tani Oh, being equipped with a laser cannon like weapon and the player has to shoot it from above.
* ShockAndAwe: The main turret has an electrical cannon that fires an electrical laser, while it also fires electrical spheres at you.
* ShowsDamage: The sections of its body appear to become increasingly damaged as you fire at those specific sections.
* WaveMotionGun: The main turret fires an electrical laser not unlike Tani Oh's cannon.
[[/folder]]

[[folder:Dai-Manji]]
The Dai-Manji is much larger than the Mini-UFOs and boasts significantly more armor and firepower. From its bottom hatch, it can send Mini-UFOs (elite mini-UFOs when its nearly destroyed) or fires a deadly beam of electricity at its target. Once its nearly destroyed, it can also launch energy bolts to carpet an area, much like the Hi-Do.

* DegradedBoss: In ''Metal Slug 3'', you have to fight them as GiantMook enemies in the final stage.
* DeathFromAbove: Has a carpet bombing like attack similar to the Hi-Do, except this one fires indestructible energy bolts.
* FlunkyBoss: Constantly spawns Mars People in flying saucers to harass the player characters.
* ShockAndAwe: Attacks with an aimed electrical laser attack.
[[/folder]]

[[folder:Rugname]]
The Rugname acts as the Martian Mothership from which troops are dispatched. It is very heavy armored, and far too large to destroy with regular weapons. It can be temporarily defeated by destroying an attached Dai-Manji. However, the only way to destroy the Rugname for good is by attacking the Martian leader Rootmars, who controls every aspect of the ship with its brain. Forcefully severing Rootmars from the ship results in total system failures, causing the ship to collapse into the atmosphere.

* FlunkyBoss: Constantly spawns Mars People in flying saucers to harass the player characters.
* MiniBoss: In ''Metal Slug 3'', you have to fight it as a miniboss in the final stage.
* ShockAndAwe: Attacks with an aimed electrical laser attack from its Dai-Manji attachment.
* ShoutOut: The way it's defeated in ''Metal Slug 2/X'' is obviously a shout out to ''Film/IndependenceDay'', where an aircraft crashes into a weakspot.
* WaveMotionGun: It's capable of firing a huge laser cannon below it.
[[/folder]]

!!''Metal Slug 3''
[[folder:Huge Hermit]]
Originally a hermit crab on Dr. Moureau's Island before it grew to a huge size, the Huge Hermit is one of the results of the nuclear strike on Dr. Moureau's Island. The rebels later capture the gigantic crab and use the shell as a tank, allowing the crab to fire the cannon.

* AdvancingBossOfDoom: It constantly advances towards the player characters, forcing them to keep moving or get crushed by it or fall into the water.
* {{BFG}}: Once it TurnsRed, the tank opens up and reveals a huge cannon that fires large bombs to destroy the terrain.
* {{Fireballs}}: What the tank shoots at you in its first phase.
* GiantEnemyCrab: An enormous hermit crab with a ''tank'' as its shell.
* StealthPun: It has a huge tank in place of a shell. In other words, it's a tank shell.
* TankGoodness: It carries an enormous tank on its back in place of a shell.
* WeaponizedAnimal: A huge hermit crab with an enormous tank for its shell.
* WarmUpBoss: Its attacks are relatively easy to avoid, and you even get a Metal Slug or a Slugnoid at the start of the battle to assist you. It becomes even easier once it stops using the fireballs and starts using the large cannon.
[[/folder]]

[[folder:The Ten Commandments Of Moses]]
This strange artifact of alien origin was created to serve as a beacon for the martians. It has turned nearly every living person around it, including scientists studying it, Rebel soldiers and even survivors of a nearby plane crash into zombies. The beacon causes a power surge that destroyed the floodlights around it, and possibly even caused the plane crash which resulted in civilians joining its undead horde. The artifact is protected by Monoeyes, 15 metre tall humanoid aliens which hover around it, the zombies it creates, and its ability to drop powerful Monoliths that crush anything beneath them.

* AbnormalAmmo: The Ten Commandments attacks by dropping monoliths on the player characters.
* CrosshairAware: It targets a player with a green laser before dropping a monolith on them.
* {{Cyclops}}: The Monoeye aliens that protect it [[ExactlyWhatItSaysOnTheTin all have a single eye]].
* DeathFromAbove: The Ten Commandments' sole attack is to drop monoliths from above that slowly sink into the ground and also act as obstacles.
* EyeBeams: The Monoeye aliens attack by firing fireball like projectiles from their eyes.
* HoistByTheirOwnPetard: Using the zombie [[BloodyMurder blood vomit]] can deal incredible damage to the Monoeyes and the Ten Commandments. This is only usable if the player gets zombified... by the very virus the Ten Commandments spread around. In fact, certain versions of the game even give you an achievement for beating them as a Zombie.
* TheMonolith: Drops monoliths with alien inscriptions on the player characters. They act as obstacles that remove themselves over time as they sink into the ground (faster if shot at).
* TurnsRed: When its health gets low, it starts glowing orange instead of green, and it drops monoliths at a faster rate.
* TheVirus: It's responsible for creating the virus that turned the people in the level into zombies.
* WolfpackBoss: The first phase has six to eight Monoeyes appear and float around the structure, and coordinate their eye beam attacks. Thankfully they're not too durable.
* ZombieApocalypse: It's the cause of the zombie virus that has infected several people in the level and possibly the player.
[[/folder]]

[[folder:Jupiter King]]
The Jupiter King is a mechanized robot created by the Rebel Army, designed to guard their secret factory. It is heavily armored in order to protect the nuclear reactor inside the robot's body. The lightly-armored head (which resembles a toy robot's head) is the weak spot of the robot. The left hand of the robot is a missile launcher, allowing the robot to fire a large number of homing missiles. The right hand of the robot is a pincer claw, which is used to destroy the ground in front of it. The robot's eyes are also capable of firing lasers to vaporize the player. It also has a "belly button" that can create a rocket, which the robot grabs and plunges into the ground.

* AttackItsWeakPoint: It is only vulnerable in the head.
* EyeBeams: It's capable of sweeping a great area with electrical eye beams.
* {{Fireballs}}: Every time it smashes the giant rocket on the ground, it'll explode into a slew of fireballs that rain down.
* HomingProjectile: The missiles it fires out will home in on the player characters.
* ImprobableWeaponUser: One of its "attacks" has it grab a giant missile and smash it into the platform, destroying that part of the platform and causing fireballs to rain down from the explosion.
* KillerRobot: A gigantic and weaponized toy robot.
* MacrossMissileMassacre: Its left arm holds a multi-missile launcher that fires destructible homing missiles.
* ShockAndAwe: Getting hit by its eye beams will electrocute the player character.
[[/folder]]

[[folder:Sol Dae Rokker]]
The Sol Dae Rokker is an instrument of the Sun God in Japanese mythology. This life form is in charge of protecting its ancient ruins from intruders. Due to the conflict of the Rebel Army and Regular Army around the ransacked ruins, Sol Dae Rokker became furious and started attacking anyone who is responsible.

* AttackItsWeakPoint: It's only vulnerable in its PowerCrystal, which is very small.
* CruelAndUnusualDeath: Getting hit by its WaveMotionGun will turn the player character into a rain of coins.
* PowerCrystal: This serves as its weakpoint and also allows it to fire its FlechetteStorm attack.
* FlechetteStorm: Fires spiked projectiles of light from its crystal. Yellow ones are aimed at random while red ones are aimed at the player characters.
* MeaningfulName: Sol Dae Rokker is a play on "Sol De Roca", which means "Sun made of rock" in Spanish.
* ShapingYourAttacks: One of its attacks consists of summoning ghostly energy wolves that act as explosive projectiles.
* TurnsRed: In both the literal and trope sense. It'll start turning red as it takes damage, and its attacks will also become faster.
* WaveMotionGun: It's capable of firing one from its "mouth". Getting hit by it will turn the player into coins.
[[/folder]]

!!''Metal Slug 4''

[[folder:Brave Gurerrier]]
This blimp, constructed by the Rebel Army and Amadeus Syndicate, is used for carrying troops to the field and to give support fire from any range.

* BackgroundBoss: It assists the Sea Satan by firing missiles at you from the background.
* CoolAirship: A huge airship constructed by both the Rebels and Amadeus Syndicate, and carries a plethora of weaponry.
* SequentialBoss: You have to fight its dorsal section, then its rear half of the gondola, then its front half of the gondola in three separate phases.
[[/folder]]

[[folder:Toschka Dalanue]]
This armed tower was created by the Amadeus Syndicate to serve as a vigilance spot and a barrier against anyone foolish enough to cross its path.

* {{BFG}}: The top section carries Big Shiee's huge cannon and fires similar explosive bullets.
* SequentialBoss: You have to fight ''five'' different "floors" of the tower.
[[/folder]]

[[folder:The Iron]]
The Amadeus Syndicate made a personal modification of the Iron Nokana, it equipped with tank treads instead of wheels so it could move faster on any terrain, and has even more improved armor and firepower. A fake Morden constantly appears to support this vehicle with his bazooka.

* TankGoodness: A modified Iron Nokana that appears to be more tank-like instead of a truck.
[[/folder]]

[[folder:Big John]]
The Big John was originally an amusement park robot, but its control was taken over by the Amadeus Syndicate and converted to a weapon, turning everyone in the park into zombies or mummies using a virus similar to what the purple gas and The Ten Commandments of Moses used.

* HoistByTheirOwnPetard: Using the zombie [[BloodyMurder blood vomit]] can deal incredible damage to it. This is only usable if the player gets zombified by the zombie virus bubbles it drops.
* TheVirus: It releases bubbles filled with the zombie virus.
* ZombieApocalypse: It's the cause of the zombie virus that has infected several people in the level and possibly the player.
[[/folder]]

[[folder:Sea Satan]]
This huge submarine is used by the Amadeus Syndicate. It can destroy ships with ease. It can also kill any personnel aboard using its Gatling Gun and dissipate its target using its missiles. It can either stealthily destroy a submarine and ship or aggressively engage them head on.

* GatlingGood: Carries a gatling gun that will fire at the player if they're on top of it.
[[/folder]]

[[folder:Amadeus Mother Computer]]
The Amadeus Mother Computer is the Amadeus Syndicate's main computer frame piloted by the Doctor.

* LoadBearingBoss: The game's not over once it's defeated, you still have to escape the exploding base.
* SequentialBoss: You have to fight the Type α Mother Computer, followed by the Type β Mother Computer, and then the main boss.
[[/folder]]

!!''Metal Slug 5''

[[folder:Metal Rear]]
This giant slug was created by the Ptolemaic Army, using data stolen from the Regular Army. It moves nimbly despite its gigantic size.

* DavidVersusGoliath: You can bring the Metal Slug to battle against it where your Slug will be the David and Metal Rear will be the Goliath.
* EvilKnockoff: It's a huge Metal Slug knockoff created by the Ptolemiac Army after they stole the Metal Slug's blueprints.
* {{Fireballs}}: Its main cannon fires large but slow moving fireballs out.
* GatlingGood: It's armed a gatling gun in the same spot that the Metal Slug has a machine gun in.
* OneHitKill: Getting crushed by it will instantly destroy the slug you're in, as well as you.
* ShoutOut: It's named after ''VideoGame/MetalGear''.
* TankGoodness: It's essentially a huge version of the Metal Slug that you ride, and comes with all the dangerous weaponry too.
[[/folder]]

[[folder:Shooting Ray]]
This Air Force unit is a large aircraft carrier created by the Ptolemaic Army that specializes in air combat.

* BulletHell: One of its attacks consists of firing a storm of flak shots forwards, when then drift back towards you in a hard-to-avoid field of bullets.
* CoolPlane: A gigantic aircraft used by the Ptolemiac Army.
* DavidVersusGoliath: You can bring the Slug Flyer to battle against it, where your Slug will be the David and the far larger Shooting Ray will be the Goliath.
* FlunkyBoss: It's capable of spawning helicopter firebombs that home in on you and can be destroyed.
* WeaponizedExhaust: One attack used by its rear section has it try to torch the player characters with its exhaust.
[[/folder]]

[[folder:Wall Crawler]]
This is a special unit created by the Ptolemaic Army. It can climb any building with ease, and also demolish the building with its sonic cannon.

* ExactlyWhatItSaysOnTheTin: It's a machine that crawls on building walls.
* FlunkyBoss: Every now and then, the commander will pop out and summon two Ptolemiac soldiers to attack you.
* HomingProjectile: It's capable of using a homing missile launcher that fires destructible missiles.
* GlassShatteringSound: Uses a sonic cannon to demolish the current floor you're on.
* WallCrawl: Like its name suggests, it's fought at the side of a building where it crawls on.
[[/folder]]

[[folder:Sandmarine]]
This is a special submarine created by the Ptolemaic Army, designed to travel under the ground.

* DeathFromAbove: One of its more deadly attacks has it fire several projectiles into the air, which then rain down randomly in huge numbers.
* MilitaryMashupMachine: It's a submarine that [[SandIsWater operates in the desert sand in place of water]].
[[/folder]]

!!''Metal Slug 6''

[[folder:Bull Drill]]
The Bull Drill is a large excavator used by the Rebels and is primarily designed to dig underground with ease. It has both a bulldozer blade and drill, hence its name.

* DishingOutDirt: It's capable of firing boulders at the player. During the second phase of the fight it can also use its drill to cause stalactites to rain down on the player.
* MilitaryMashupMachine: A cross between an excavator and a drilling machine.
* ThisIsADrill: It's capable of using its excavator drill to make rocks land on the area, and to attack.
[[/folder]]

[[folder:Iron Sentinel]]
This is a large rocket launching tank operated by General Morden that will keep sliding down the slope until you destroy it. It is heavily armored, meaning the weak spot is the giant cannon on top. It is also armed with a missile launcher and energy cannons.

* DeathFromAbove: One of its attacks has it launch a ''huge'' rocket into the air that will then crash into the ground and cause a fiery shockwave.
* InterestingSituationDuel: You fight on the side of this thing as it slides down a hill.
* MacrossMissileMassacre: Most of its attacks consist of launching several rockets in various patterns at you.
[[/folder]]

[[folder:Brain Robot]]
The Brain Robot is a large robot controlled by an artificial brain. The brain is housed inside a glass dome in order to protect and preserve it. It also has eyes, connected to the brain through nerves. This may imply that the eyes previously belonged to the same creature as the brain.

* AdvancingBossOfDoom: It'll advance in on the player when it's moving, forcing you to keep moving backwards.
* BerserkButton: Bait it into using its melee attack too often or take too long to defeat it and it will keep swinging its arms while moving, limiting your safe space. You'll know it's pissed when it does an angry stomping motion.
* BrainInAJar: Its head appears to have a huge alien brain within that controls the robot.
* CarFu: One of its attacks consists of grabbing a wrecked truck from the sewage and tossing it at you.
* EnergyBall: Its brain fires these out forwards, which then stop before aiming and flying at the player characters.
* KillerRobot: It's an alien BrainInAJar robot that's hell-bent on chasing and killing you.
* ShockAndAwe: It's capable of shocking the entire floor with electricity. To avoid this, you need to stand on one of those boxes that appear in the arena.
[[/folder]]

[[folder:Sea Worm]]
The Sea Worm is an Invader worm with deadly acid spitting capabilities and some level of flight.

* AttackItsWeakPoint: Its head is the primary weakspot.
* SandWorm: A sea variant instead. It also acts as a SegmentedSerpent.
* SuperSpit: It's capable of spitting purple acid at the player characters or even spewing a huge stream of the stuff.
[[/folder]]

!!''Metal Slug 7/XX''

[[folder:Worm Mecha]]
Morden used this drill mech to attack the incoming Regular Army soldiers. One attack includes using its drill to either dig up from the ground to hit the player(s) or to fire explosive debris at them. It will also fly over the player(s) to fire turrets and rebel soldiers from its hatches of each segment. It will also launch a saw that throws explosive debris.

* DeadlyDisc: Capable of launching a huge saw disc that advances towards you.
* {{Foreshadowing}}: The Kraken's tentacles are pretty much recolored and smaller versions of the Worm Mecha's sprites.
* SegmentedSerpent: Each of the segments are destructible and will help with lessening its firepower.
[[/folder]]

[[folder:Crablops]]
A giant one-eye crab shaped robot. Its head and arms can be separated from its body.

* BackgroundBoss: In its first encounter, it attacks you from the background, to the point where only its hands are attackable. You need to shoot the rocket minecarts so they'll launch a missile in the air that will hit it.
* BossArenaIdiocy: Minecarts carrying rockets will constantly spawn at the bottom of the area, and shooting them will cause them to launch a missile at Crablops for huge damage.
* CyberCyclops: Like its name suggests, it has a single mechanical eye.
* DetachmentCombat: The second battle against it reveals that it can detach its head and torso from its legs, and [[DualBoss both are fought as separate enemies]].
* DishingOutDirt: Both encounters with it has it capable of grabbing a stalactite from the cave ceiling and dropping it on you.
* DualBoss: In Mission 3, its head and arms detaches from its body and you have to fight both of them.
* EyeBeams: It attacks you with these in its first encounter.
* FlunkyBoss: Capable of deploying containers that spawn mole drones to attack you. The second time it's fought, it also drops exploding maggots and rebel soldiers.
* GiantEnemyCrab: It's a crab-like mecha with the capability of splitting into two, and also has a lot of firepower.
* InterestingSituationDuel: Partway through the second encounter, you'll board a diagonal platform lift. Once one of the halves is down, the other will attack you more relentlessly as the life ascends.
* MacrossMissileMassacre: It has a multi-homing missile launcher on its head, which it'll use in its first encounter.
* MeaningfulName: It's a crab-like robot. It has one eye. Hence, it's a crab cyclops.
* NotQuiteDead: When defeated in Mission 2, it's seen relatively intact, if powered down. Sure enough, it returns as the boss of Mission 3.
* PuzzleBoss: In its first encounter, you're only able to attack its arms. In order to do good damage to it, you need to shoot the conveniently-placed rocket carrying minecarts so they'll launch a missile into the air that will hit its body.
* RecurringBoss: It's fought as both the second and third boss of the game, except in different situations.
* WeaponizedExhaust: Its bottom half is capable of using an exhaust cannon during the second time it's fought, once the top half is destroyed.
[[/folder]]

[[folder:Fall Mecha]]
A gorilla-crab like mecha designed to climb up the cliff. It is armed with several weapons such as missile launchers and a laser cannon.

* AmbiguousSituation: It's left ambiguous if it's truly destroyed since it doesn't explode when defeated, instead using a WaveMotionGun to propel the player characters up to the level endpoint.
* FlunkyBoss: It will often summon two turrets on the waterfall face that fire various types of attack at you.
* InCaseOfBossFightBreakGlass: Its weakpoint is the glass-looking case in its middle, once its head armor is destroyed.
* InterestingSituationDuel: You fight it as it climbs up a waterfall, and the platforms you stand on is the boss itself and its arms.
* KillerGorilla: A mecha that appears to resemble a gorilla in terms of body shape.
* WaveMotionGun: Once its top armor is blown off, it becomes capable of firing one out down the middle. It also uses one upon defeat, although this doesn't hurt you and instead propels you to the level endpoint.
[[/folder]]

[[folder:The Union]]
A trio of vehicles consisting of a Head Tank (01), a VTOL (02), and a Slave Tank (03) with the ability to combine with each other. All three of them need to have their weakpoints destroyed in order to be beaten.

* AttackItsWeakPoint: They're only vulnerable in the bright red cores on each of them.
* BossArenaIdiocy: If the head tank didn't have a convenient platform at its base for the player to stand on, it would be ''far'' more difficult to hit the Slave Tank. Likewise, if it didn't have a convenient area to stand on right in front of its weakpoint, it would be a lot more tricky to hit.
* CombiningMecha: The three of them can combine together into a larger form. While they aren't quite threatening in this form, they can crush any player characters between any of the parts when they do so.
* DeathFromAbove: The Slave Tank is capable of firing several bombs into the air that rain on the player.
* FlunkyBoss: The VTOL can summon elemental pod enemies to attack the player.
* GatlingGood: The VTOL has a gatling gun attachment on its front side.
* ICanStillFight: Destroying the core on one of them does not take it out of the battle, and it can still attack and move like normal. The fight's only over once all three lose their cores.
* InCaseOfBossFightBreakGlass: Their weakpoints appear to be red glass-looking cores.
* InterestingSituationDuel: The entire fight takes place on the three of them, where your player character uses them as makeshift platforms.
* KilledOffscreen: When all three are defeated, your character leaps off as the trio move offscreen. After some explosion sounds and screen shaking, their wreckage then flies back on-screen from the right.
* MeaningfulName: The trio is collectively known as the Union, can combine with each other, and all three of them need to be destroyed to defeat them.
* ShoutOut: Being made of three different parts with an odd core-looking weakpoint in each of them, it's a reference to the fifth boss of ''VideoGame/{{RType}}''.
* WolfpackBoss: You fight all three of them at the same time.
[[/folder]]

[[folder:Rebel Gigant]]
A huge mech that developed by the future rebel army that was bought into the present day. It is specifically designed to be controlled by Allen O'Neil. Despite its huge body and very tough armor, it has great agility. It's also equipped with various weaponry such as Homing missiles, and Floating mines.

* DuelBoss: The boss battle consists of the player's Slug Gigant versus Allen O'Neil's Rebel Gigant, with no flunkies between you and him. You're forced to fight on a Slug -- if your Slug Gigant gets destroyed, you automatically die and respawn with another Slug Gigant.
* EvilCounterpart: It's essentially a rebel army version of the Slug Gigant.
* HumongousMecha: It's far larger than most of the pilotable mechs in the series.
* MacrossMissileMassacre: It's equipped with a multi-homing missile launcher on its shoulder and Allen won't hesitate to spam it.
* MirrorBoss: You face it when piloting your Slug Gigant. In fact, if your Slug gets destroyed, you die and you'll respawn with another Slug Gigant.
[[/folder]]

[[folder:Kraken]]
Kraken is an ultimate weapon brought by the Future Rebels to help launch another Morden coup d'etat. It is equipped with with super thick photon armor which even protects it from lava as well as various weaponry from the future, such as cylinder grenades, and an ultra huge cannon. It is also equipped with armed tentacles for recharging its energy with lava.

* BattleAmongstTheFlames: You face it at a lava field with floating scrap metal.
* {{BFG}} The main unit comes equipped with a huge cannon that destroys the scrap metal platforms on the lava.
* CombatTentacles: Eight of them, no less, and all of them are capable of using their own attacks. You need to destroy each individual one before the main head attacks you.
* DeathFromAbove: The main unit capable of raining fireballs onto you or dropping cylinder grenades from above
* GameplayAndStorySegregation: It's capable of travelling under the lava, yet the Flame Shot will still damage it despite being less hot. Granted, you don't get the Flame Shot during the battle itself.
* MarathonBoss: The fight is separated into five phases, the first four involve destroying two of its eight tentacles, and the last being an attack on the main machine itself. Each tentacle has a good bit of health to complicate things.
* SequentialBoss: The first phases involve attacking and destroying its tentacles, before you can actually fight the main unit.
* ShoutOut: Its design appears to be like that of the [[DualBoss Trumpet Lillies]] from ''VideoGame/InTheHunt''.
[[/folder]]
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