Characters / Metal Slug

Despite the fact that the plots of the games usually appear barebone, Metal Slug 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 here.

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Protagonists (Broken down by game appearance)

Metal Slug

     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:

  • All-American Face: More or less designed as the typical American war movie hero.
  • Berserk Button : Anything involving General Morden.
  • Big "NO!": He lets out one for his death cry.
  • Boring, but Practical: 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.
  • Eagle Land: He's a tanned, blonde-haired American who loves big guns and justice.
  • Emergency Weapon: 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.
  • Extendo Boxing Glove: An alternate melee attack for when he's crouching.
  • Handguns : His attack power is doubled while firing a handgun.
  • The Hero: The leader of the team and the poster boy of the series.
  • Heterosexual Life-Partners: With Tarma, who has been with him since the very beginning.
  • "Open!" Says Me: An alternate melee attack when he opens chests is to simply kick them open.
  • Overprotective Dad: Put a programming lock on ALICE to keep certain ďadultĒ terms, particularly those dealing with charm and seduction, from even entering her vocabulary.
  • Playful Hacker : During his spare time. He accidentally almost launched nuclear weapons at one point.
  • The Smart Guy: Outside the battlefield he's an expert hacker.
  • Truly Single Parent: He's the "father" of MS-ALICE.
  • Vitriolic Best Buds : With Tarma
  • Weapon of Choice: The Heavy Machine Gun, but initially it was the standard Pistol.

     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:

  • Ace Pilot: 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.
  • Badass Biker: Off-screen. The Cool Shades and his backstory of expertly building bikes establish him as this.
  • Cool Shades: Never seen without his shades. It also helps distinguish him from Marco at a glance.
  • Demoted to Extra: Becomes a supporting character in 4, but regains his playable status in 5.
  • Gadgeteer Genius : He's the team's Slug expert, largely due to him tinkering with vehicles in his spare time.
  • Glass Cannon: In Defense, he has the lowest HP of the four main characters but his Shotgun does the most damage.
  • Heterosexual Life-Partners: He's the only character who has been with Marco from the beginning.
  • Meaningful Name: As the Metal Slug technician of the team, his name last name is Roving.
  • The Lancer: Marco's best friend and foil, as well as the default player 2.
  • Percussive Maintenance : His Slug Kick. Sometimes averted, causing damage to the Slug instead.
  • Precision F-Strike: He lets out a huge F-Bomb as his death cry when killed.
  • Vitriolic Best Buds : With Marco.
  • Weapon of Choice: The Shotgun.

Metal Slug 2

     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:

  • Action Girl: Kicks as much ass as any of the men.
  • Badasses Wear Bandanas: She always wears one in nearly every appearance.
  • Bare Your Midriff: Setting a trend, her military "uniform" exposes her belly.
  • Brutal Honesty: 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.
  • The Big Girl: While the whole team packs plenty of power, she's the explosives specialist.
  • Compressed Hair: Hidden in her bandana in her sprites. Some pieces of official art would have some of her hair spew out of her back head.
  • Dark and Troubled Past: 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.
  • Demoted to Extra: Becomes a supporting character in 4, but regains her playable status in 5.
  • Heterosexual Life-Partners: With Fio.
  • Informed Loner: 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.
  • In-Series Nickname: "Memphis Bomb Princess".
  • Japanese Delinquents: A variation. Eri was a former sukeban (female gang leader) and she still sports blond hair.
  • Kick Chick: She can sometimes use kicks as a melee attack animation.
  • 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.
  • Sdrawkcab Name: Spelling her name backwards in Hiragana will get the name of a famous Japanese pop star Rie Tomosaka.
  • Stuff Blowing Up: Starting in 6 her specialty is grenades.
  • Tomboy and Girly Girl: Eri's the Tomboy. Her backstory, attitude, and appearance are much tougher than Fio's.
  • Weapon of Choice: The laser.
  • Younger Than They Look: Eri's two years younger than Fio, considering Eri's tougher personality.

     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:

  • Action Girl: No less a capable fighter than any of the men.
  • Badass Adorable: Best exemplified by her victory animation of her falling down coquettishly. Mind you, this is after wiping out hundreds of enemy troops.
  • Bare Your Midriff: As is the norm with female fighters in the Metal Slug universe.
  • The Chick: The medical expert of the team and also the most emotional.
  • Finger Poke of Doom: Her melee attacks include swift tonfa strikes, hatchet slices, and sissified slapping and shoving. Enemy soldiers die horribly all the same.
  • Girly Bruiser
  • Guest Fighter: She is playable in The King of Fighters: Maximum Impact 2.
  • Heterosexual Life-Partners: With Eri.
  • Heroic Self-Deprecation: She usually thinks less of herself in comparison to her teammates.
  • Last of Her Kind: Fio's parents' greatest fear. See Stay in the Kitchen below.
  • Meganekko: An archetypical example in video games. She's got the cute look, modest personality, and is overall moe because of it.
  • Miss Fanservice: 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).
  • More Dakka: Her Specialty from Metal Slug 6 onwards. The Heavy Machine Gun is basically her default weapon.
  • Nice Hat: She wears one in almost every appearance.
  • Older Than They Look: Despite her appearance and character, Fio is two years older than Eri.
  • Small Girl, Big Gun: The heavy weapons specialist is the smallest of the four main playable characters.
  • Stay in the Kitchen: 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 (Last of Her Kind and thus putting the whole family line in danger since she has no children of her own) is up for debate (possibly both).
  • Took a Level in Badass: 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.
  • Tomboy and Girly Girl: Fio's the Girly Girl compared to Eri's Tomboy. She's got a sheltered background, cuter looks, and is much less hardened in general.
  • Weapon of Choice: The Rocket Launcher, but initially it was the Heavy Machine Gun.
  • Wimp Fight: Believe it or not, this is one of her melee attack animations, but it's subverted in that it can damage or even kill any human-sized enemy with her sissy flailing.

Metal Slug 4

     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:

     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:

Metal Slug Advance

     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.

     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.

Metal Slug Mobile

    Nathalie Neo 
A member of the Sparrows division.

    Roberto Nicola 
A member of the Peregrine Falcons.

  • Ascended Fanboy: Was overjoyed to work with Fio, one of his favorite soldiers.
  • Bash Brothers: Works with Leona in games he stars in. In Metal Slug Attack, he is partnered with Fio.
  • Limit Break: The Roberto Combination, which is a set of shots from his gun and some bomb throws.
  • Trauma Button: 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.

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


Ikari Warriors

Ralf and Clark, in between their appearances in The King of Fighters 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.

     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.

     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.

     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:

    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:

  • Cast Herd: 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.
  • Last Episode, New Character: Whip and Heidern were the final units implemented in Metal Slug Defense.
  • Revolvers Are Just Better: Her special attack is shooting a bullet from a golden revolver. Its range is short in Defense and much farther in Attack.
  • Whip It Good: Her standard attack. Her whip is able to cause knockback in Attack.

     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

  • Cast Herd: 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.
  • Early-Bird Cameo: Appeared as a drill instructor in Defense's Combat School before becoming a playable unit.
  • Hired Guns: The leader of the Ikari Warriors, who sends his troops to the Regular Army whenever there's a big conflict.
  • Last Episode, New Character: Whip and Heidern were the final units implemented in Metal Slug Defense.
  • Life Drain: His special attack has him jump and suck the life of the closest unit.
  • Precision F-Strike: Go. To. HELL!
  • Razor Wind: His long-range attack.


Antagonists (By faction)

Rebel Army

     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 A Father to His Men, 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

  • Big Bad: For most games, though sometimes he gets the title hijacked.
  • Big Damn Heroes: If you took the top path in Mission 4 in Metal Slug 6, he appears to save you from a great fall after the invader queen dies.
  • Butt-Monkey: Appearing on screen is usually a sign that he'll suffer a Humiliation Conga.
  • Cool Plane: 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.
  • Evil Laugh: Tends to laugh in a mocking tone upon approaching the player.
  • Eviler Than Thou: Frequently on the receiving end of this.
  • Eyepatch of Power: The man certainly looks imposing thanks to his eyepatch.
  • Final Boss: Of the original and of 7/XX.
  • Joker Immunity: Despite being defeated and/or double crossed whenever he appears, he always survives to lead his army again.
  • Made of Iron: When riding in the Hi-Do in the first game, he can take even more bullets than Allen O'Neil.
  • Made of Plasticine: Applies to his troops.
  • Not Me This Time: 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.
  • Too Dumb to Live: 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.
  • Well-Intentioned Extremist: 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.

     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:

  • A Day In The Lime Light: 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.
  • Annoying Laugh: 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.
  • Boss Banter:
    • "C'MON, BOY!"
    • "YOU'RE MINCEMEAT!"
  • The Dragon: To Morden. Also doubles as The Brute.
  • Duel Boss: 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, It turns out to be a duplicate.
  • Engrish: "GO HOME TO MOMMY!"
  • Joker Immunity: 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.
  • Lightning Bruiser: Despite being bigger than the playable characters, he's also faster than them.
  • Implacable Man: He cannot be stopped. Just shooting him alone is barely going to phase him.
  • Improbable Weapon User: Get too close to him and he'll slap you with the ammo belt of his machine gun.
  • Large Ham: He's the only character in the Metal Slug franchise to actually have spoken lines. And they are ALL taunts!
  • Made of Iron: He's a human (except in 4), just like the player characters. Unlike the player characters, he has an obscene amount of health for a human, being able to last longer than a tank!
  • Mirror Boss: 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, he takes several.
  • See You in Hell: His death cry.
  • Turns Red: His skin turns red as he takes more damage and speeds up.
  • Unexplained Recovery: 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.

     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:

  • Bad Boss: 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.
  • Dummied Out: Sprites of Abul attacking and setting up his white flag are present in 2's ROM. These get their use in Defense and Attack.
  • Hoist by His Own Petard:
  • I Shall Taunt You: Shows up multiple times commanding his troops and taunting the player.
  • Know When To Fold Them: Waves a white flag once things go bad for him.
  • Starter Villain: 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.
  • The Unfought: The player ends up fighting the mission's boss while ignoring Abul in the background.
  • White Flag: Raises one on his sword when he surrenders after things go south.

     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.

     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

  • In the Blood: 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.
  • The Mole: He infiltrated the Regular Forces training camp by posing as a drill instructor.
  • Pistol-Whipping: 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.

Martians

     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:

  • Aliens Are Bastards: They just want to conquer and destroy without much backstory.
  • Alien Blood: They bleed green.
  • Brain in a Jar: The Ring Laser Mecha units are operated by a brain in a jar.
  • Chronic Backstabbing Disorder: They betray Morden twice, for no reason other than because they can.
  • Enemy Mine: They team up with both the Rebels and the Regular Army to fight an even greater threat, the Invaders.
  • Everything's Squishier with Cephalopods: Resemble giant squid or octopi.
  • Expy: They look exactly like H. G. Wells' martians.
  • Flying Saucer: Their main vehicle. Some of their units are unmanned ones that fire a laser. Their mothership is an even bigger one.
  • Giant Space Flea from Nowhere: In Metal Slug 2. Not so much in X, where they are foreshadowed better.
  • Hoist by His Own Petard: Both their betrayals of Morden and the Rebel Army lead to an Enemy Mine that causes their defeat. The first time because a pilot from the Rebel Armor 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.
  • Homing Projectile: Martians primarily attack with three homing nuclei-like projectiles. Thankfully said projectiles are destructible.
  • Last Episode, New Character: They show up in the last level of 2. Averted in X where they appear in earlier levels.
  • Oh, Crap!: Their standard reaction when the Invaders show up.
  • Ray Gun: They wield these, just like classic aliens... although said guns tend to fire out slow, homing, destructible nucleus-like projectiles.
  • Starfish Aliens: They resemble giant jellyfish/squid. Yet they have skulls, green blood, and mouths.
  • The Worf Effect: After establishing themselves as the premier threats of 2/X and 3, they're easily taken down, captured and imprisoned, and even eaten for breakfast by the Invaders in 6.

     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:

  • Big Bad: Of 3.
  • Big Damn Heroes: If you took the bottom path in Mission 4 in Metal Slug 6, he appears to save you from a great fall after the invader queen dies.
  • Eldritch Abomination: He may look like E.T., but he does it Lovecraft-style.
  • Enemy Mine: 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.
  • Final Boss: Of 3.
  • Free-Fall Fight: You fight him while you and the soldier you rescued (and another player, if any) fall down to Earth.
  • Good Scars, Evil Scars: He has a number of Frankenstein-like stitchings on him.
  • Greater-Scope Villain: 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.
  • Large and in Charge: The normal Mars People are human-sized, he takes up most of the screen you fight him on.
  • My Brain Is Big: Bonus points for it actually being visible, encased in a dome.
  • Promoted to Playable: 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 Smart Bomb.
  • Psychic Powers: Fitting for an alien with a giant brain, it has psychic powers.
  • Super Intelligence: Part of the reason he's the leader of the Mars People.

Ptolemaic Army

     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 Brotherhood of Nod.
  • Knight of Cerebus: While Metal Slug 5 has most of the series usual silliness, the Ptolmaic Army's typical soldiers lack the silliness of the Rebel Army.
  • Power Copying: They specialize in stealing technical plans from the Regular and Rebel Army.
  • Religion of Evil: They are led by Ptolmaic Shamans, and apparently worship Evil Spirit Incarnate.

     Evil Spirit Incarnate 
Debut: Metal Slug 5

http://static.tvtropes.org/pmwiki/pub/images/bc04728b_1d9a_4857_9070_582cb86b8a20.jpeg

The Final Boss of Metal Slug 5, a huge Grim Reaper 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 Final Boss.

     Ptolemaios 
Debut: Metal Slug Attack

Originally meant to be the Final Boss 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:

  • Bad Future: 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.
  • Big Bad: Informally in 5. In Attack, he is this to Red Goblin.
  • The Cameo: Mostly unintentional, but his towers (as well as the Stone Turtle and the Elephants) can be seen in the background of Mission 5.
  • Came Back Strong: Every death he suffers results in him getting new attacks.
  • Death from Above: Drops Rosetta stones on top of the opposing team.
  • Dummied Out: A nearly complete set of sprites is present in Metal Slug 5. Most of them are given use in Attack.

Invaders

     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:

  • Alien Blood: They bleed purple, in contrast to the Mars Peoples' green.
  • Aliens Are Bastards: Even moreso than the Mars People.
  • Always a Bigger Fish: 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.
  • The Dreaded: The Mars Peoples' reaction when these guys appear is to cower in fear. And rightfully so.
  • Evil Is Visceral: They have an organic lair as opposed to the Mars Peoples' technological one.
  • Food Chain of Evil: Think the Mars People were deadly? These guys literally eat Mars People for breakfast.
  • Giant Enemy Crab: The Crab-tanks and Vanguards.
  • Knight of Cerebus: The Mars People have an Oh, Crap! reaction when they show up and eat them at the end of Mission 2. The final mission also has a Dark Reprise of the classic "Final Attack" theme.
  • Heli-Critter: The Smashers, which spin their legs to fly in the air like a helicopter before inflating themselves to crash down on you.
  • Horrifying the Horror: 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.
  • Puppeteer Parasite: 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.
  • Spin Attack: The lowest ranking mooks move around via spindashing.
  • To Serve Man: 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.
  • Unique Enemy: There's a Gold Hunter Walker encountered if you take a secret path in the final mission, killing it grants 50000 points.
  • Zerg Rush: The standard troops ambush in groups. In Mission 3, a large horde of them come spinning down from the right side.

     Invader Queen 
Debut: Metal Slug 6

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

  • Background Boss: Most of the boss is in the background- you need to attack her head to damage her.
  • Big Bad: The leader of the Invaders in 6.
  • Disney Villain Death: Falls to her death before explodes in a massive explosion.
  • Eye Beams: Purple ones that aim at you.
  • Final Boss: Of 6.
  • Flechette Storm: 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.
  • Hold the Line: The final part of the battle turns into a Free-Fall Fight where she's invulnerable, sending huge waves of destructible projectiles dowanwards at you.
  • Large and in Charge: She's one of the biggest Invaders there.
  • Trick Boss: 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.

Others

     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.....

  • The Cracker: The Amadeus Syndicate are a team of cyber-terrorists.
  • Elite Mooks: The disguised Amadeus troops use Heavy Machine Guns in the final level.
  • Everyone Calls Him "Barkeep": Amadeus is referred to as "Doctor" in Metal Slug Attack.
  • Evil Old Folks: Amadeus himself
  • Framing the Guilty Party: 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.
  • Mecha-Mooks: Employ a lot of these.
  • Palette Swap: In Attack, the Infantry are purple colored Rebel Soldiers.
  • Robot Me: Robot Mordens and Allen O'Neils.
  • Synthetic Plague: They managed to harness the Mummy and Zombie viruses from the previous games.
  • Villain Team-Up: 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 the Syndicate's supervirus doing all the dirty work for her own.

     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:

  • Abusive Precursors: Oguma and his people essentially began life on Earth, but they have no problem snuffing it out in pursuit of their goals.
  • Affably Evil: Speaks in a very polite and calm voice.

     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:

  • Actually Four Mooks: Subverted. While the Pharaoh's Arc consists of multiple mummies on a chariot, they are all part of the same unit.
  • Distracted by the Sexy: The Mummy Cats' main way of luring their enemies.
  • Dub Name Change: The Mummy Cats are called Sexy Mummies in Japan.
  • Enemy Summoner: 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.
  • Kill It with Fire: The Mummy Warrior uses a long torch as his weapon.
  • Palette Swap: The Lovely Mummy is a red colored version of the Mummy Cat.
  • Support Party Member: The Mummy Cat is awkward to use, but three of her four skills involve increasing the strength of Mummies, Mummy Warriors, and Mummy Dogs.
  • Villainous Breakdown: The Pharaoh turns green in rage alongside his minions after being defeated. As the Tyrant Pharaoh, he starts commanding in a furious manner.


Support Characters and other notable NPC's

     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:

  • Action Girl:
    • 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 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.
  • Beware the Nice Ones: These two have some obscenely powerful Normal attacks in Attack.
  • Butt-Monkey: 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.
  • Combat Medic: Madoka's special in Attack heals friendly troops.
  • The Chick: 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.
  • Cute Clumsy Girl: Given the above. It's taken even further in 3D when Rumi tries a dynamic entrance from a helicopter and screws it up.
  • Fanservice Pack: 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.
  • In-Series Nickname: "The Wandering Ghost"
  • It Runs in the Family: Both sisters being terrible with directions.
  • The Medic: 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 Combat Medic 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.
  • Motor Mouth: 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.
  • No Sense of Direction: Though they count as P.O.W.s, they are never caught by the enemy. They just happened to wander through the area.
  • Older Than They Look: Despite being a Palette Swap, Madoka is eleven years older than Rumi.
  • Out of Focus: 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.
  • Palette Swap: Madoka has brown hair and grey attire compared to Rumi's blonde hair and green attire.
  • Pint-Sized Powerhouse: Both walk and carry an overly large backpack holding various ammunition and food items. Downplayed as they seem to be struggling to keep balance.
  • Series Continuity Error: Metal Slug 3D has Rumi ranked as a Corporal even though she's a Sergeant in every game she appears in.
  • Stun Guns: Madoka's close range attack in Attack.
  • Timed Mission: 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.
  • Unusually Uninteresting Sight: 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.
  • Wimp Fight: One-sided in Attack, Rumi flails her hands rapidly if anyone gets close to her; it's still enough to knock them out.

     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:

     Utan 

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

Utan Tropes:

  • Gag Penis: If you look at his Idle Animation 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 monkey dong instead, blushes and quickly stuffs it back inside.
  • Stock Animal Diet: As a monkey, he eats bananas.

Combat School Instructors

     Sophia Greenville 

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

Sophia Tropes:

  • Ascended Extra: 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).
  • Babies Ever After: Margaret, the instructor from Metal Slug X hints that Sophia retires to raise a family.
  • The Bus Came Back: Shows up with Margaret in the second and third Pachislot games in Japan. In the West, it is in Metal Slug Defense.
  • Ms. Fanservice: There's a good amount of art dedicated to her in the art galleries of the home versions.
  • Passionate Sports Girl: What made her easily excel as a member of the Peregrine Falcons. Her favorite sport is Basketball, and also dabbles in bass fishing.

     Margaret Southwood 

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

Margaret Tropes:

  • Ascended Extra: 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.
  • Art Shift: Metal Slug Defense uses her sprites in X for the Events and her new artwork for the Combat School.
  • Drill Sergeant Nasty: A jerk to you on the lower ranks, although she'll soften up as you rise among the ladder.
  • Early Installment Character-Design Difference: Wore a green military dress in X before changing to a blue dress for Second Mission onward.
  • Easter Egg: Touching her breasts in Metal Slug Defense will cause her to react depending what rank you are in.
  • Eyes Always Shut: If she opens them, you've either impressed her, or you've made a complete ass of yourself.
  • Hair Color Dissonance: It's uncertain if her hair is blonde or lightish brown but sometimes her hair is represented by a darker shade of brown.
  • Like a God to Me: Hitting the Super Devil rank will make her admire you to the point of calling you "Her Majesty".

     Riviera "Lilly" von Wittenberg 

One of the two drill instructors in Metal Slug 6.

Lilly tropes:

     Maryell "Mary" von Wittenberg 

One of the two drill instructors in Metal Slug 6.

Mary tropes:


The Slugs

     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

  • A.I. Is a Crapshoot:
    • 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.
  • Armored Coffins: There's no way to easily bail out of the 000. Either you get out after defeating all enemies or letting it explode.
  • Armor-Piercing Attack: 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.
  • All Your Powers Combined: The Type-B has the positive traits of the Experimental and the Type-R
  • Backwards-Firing Gun: 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.
  • Bonus Boss: Fighting the Black Hound is entirely optional in a secret area, and it gives no reward.
  • Discard and Draw: 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.
  • Escape Pod: They are equipped with a floatation device, which is buoyant enough that the player can survive falling from space with it.
  • Homing Projectile: The Black Hound uses this when it becomes playable in Advance. A rapid fire version of it, too.
  • Mini-Boss: The Black Hound first appears as an optional boss in 5 before becoming playable in Advance.
  • Mighty Glacier: 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.
  • Promoted to Playable: 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.
  • Red Ones Go Faster: The Type-R is orange.
  • Super Prototype: 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.
  • Suicide Attack: Pressing Fire and Jump while in it will cause it to rush forward and explode.

     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

  • Action Bomb: 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.
  • Breakable Weapons: It loses its cannons when damaged. After taking two hits, it's left without any vulcans.
  • 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.
  • Glass Cannon: 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.
  • In a Single Bound: The Slugnoid's specialty, which is improved even more for the Slugnoid Type-B.
  • Jump Jetpack: Its high jumps are jetpack-assisted.
  • Molotov Cocktail: Certain versions of the Slugnoid have an incendiary bomb as their bomb ammo, setting the floor underneath on fire.
  • More Dakka: It has two cannons as opposed to one.
  • Nerf: X makes some levels harder by replacing the SV-001 with the more awkward Slugnoid.
  • Red Ones Go Faster: The Type-R, but it's still not as fast as even the SV-001 Experimental.
  • Shows Damage: Taking damage causes the Slugnoid to lose a gun.
  • Walking Tank: It's on two short, if stubby, legs.

     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

  • 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.
  • Denial of Diagonal Attack: 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.
  • Fragile Speedster: 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.
  • Lovable Coward: 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.
  • Truth in Television: Camel-mounted machine guns actually existed in real life, called zamburaks.
  • Weaponized Animal: A camel with a rapid-fire zamburak attached to its side.

     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

  • Cool Plane: 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.
  • David Vs Goliath: 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.
  • Homing Projectile: Its missiles orient themselves slightly on their own.
  • Jet Pack: Starting in 3, many of them contain a jetpack and goggles for the player, for if the Flyer gets destroyed.
  • This Looks Like a Job for Aquaman: It's usually only available when enemy planes are about, an exception being 2/X where it can be used against the Dragon Nosuke.
  • Unexpected Shmup Level: Tends to appear in several Shoot 'em Up-like segments of the games.

     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

  • Fire-Breathing Diner: To gain the ability to shoot fireballs, it must pick up a hot pepper.
  • Lightning/Fire Juxtaposition: The two Mutually Exclusive Powerups 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.
  • Mighty Glacier: 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.
  • "Shaggy Dog" Story: 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.
  • Shock and Awe: It can breathe electricity if it eats a car battery.
  • Trampled Underfoot: It can kill a zombie merely by walking over it.
  • Weaponized Animal: An elephant with a gun attachment to it. It can even eat peppers or batteries for it to use fire or electrical attacks!

     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

     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.

  • Denial of Diagonal Attack: 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.
  • Fragile Speedster: 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.
  • Weaponized Animal: An ostrich with a rapid-fire gun attached to its side.

    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.

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

Bradley Slug tropes

  • Cutscene Power to the Max: 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.
  • Good Colors, Evil Colors: Bright Green to represent the Regular Army, as opposed to the grey/dark green of the bad guys.
  • Glass Cannon: It houses one of the most powerful secondary fires available, but is very fragile.
  • How Do I Shot Web?: 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.
  • Jump Jetpack: Is jumps with the help of a thruster beneath its treads.
  • Mercy Invincibility: Subverted. It receives no invincibility and can even be hit multiple times with the same bullet.

     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).

  • Ambidextrous Sprite: The Slug Gunner swaps its weapons while turning.
  • Awesome, but Impractical: 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.
  • Close-Range Combatant: 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.
  • Denial Of Diagonal Attac K: The LV Armor has a major deficiency in its ability to shoot diagonally, which even applies to heavy machine gun ammo.
  • Double Jump: Most kinds can use rockets to boost itself once in the air.
  • Gatling Good: One of the Slug Gunner's arm is equipped with a gatling gun.
  • Mini-Mecha: They are mechas as large as the slug units.
  • Transforming Mecha: The SVW-001 can morph between a Tank and a Mecha.
  • Pile Bunker: The Slug Gunner has a pile bunker powered by revolving chamber.
  • Super Prototype: For those who prefer speed over mobility, the Proto Gunner is actually better.

Bosses

    In general 
  • Evil Is Bigger: 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).
  • Vehicular Assault: Most of the bosses are a huge vehicle or robot of sorts that the player has to fight on foot or in a Slug.

Metal Slug

    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.

  • Cool Plane: Albeit one that doesn't fly.
  • Stationary Boss: Doesn't move from its spot, due to having crash-landed and made into a stationary base of operations.
  • Warm-Up Boss: All its attacks are relatively easy to avoid.
  • Wave Motion Gun: It can charge up with one of these and fire. Either crouch or stay on higher ground to avoid it.

    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.

  • Boss Arena Idiocy: 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.
  • Cool Plane: Unlike the Tetsuyuki, this one does fly.
  • Recurring Boss: It also appears in Metal Slug 3 as one of the minibosses in the final level. Allen pilots it this time.
  • Traintop Battle: Its encounter in Metal Slug 1 has you battle it on a moving train.
  • Villain: Exit, Stage Left!: 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.

    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.

  • Land Mine Goes "Click!": Its side launchers can fire landmines.
  • Meaningful Name: Tani Oh means Valley King in Japanese. Appropriately enough you encounter it at the top of a valley.
  • Samus Is a Girl: 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.
  • Tank Goodness: A huge Rebel army tank with a laser cannon/railgun type weapon and mine launchers.
  • Wave Motion Gun: The main cannons fire some sort of laser or railgun type weapon that hits anything in its range instantly.

    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.

  • Degraded Boss: 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.
  • Dual Boss: You fight both of them at the same time.
  • Mini-Boss: Shoe is encountered as one in Mission 5 of both the original game and X.
  • Tank Goodness: Two large Rebel army tanks with fireball cannons and missile launchers.

    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.

    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.

  • Destructible Projectiles: 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.
  • Death from Above: It's capable of using a carpet bombing attack where it drops bombs all over the area.
  • Final Boss: The last battle of Metal Slug 1, where Donald Morden himself pilots this.
  • Homing Projectile: Its missile attack will home in on the player.
  • Macross Missile Massacre: Has a missile launcher on its front that shoots a swarm of homing missiles.

Metal Slug 2/X

    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.

  • Demoted to Extra: 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.
  • Car Fu: In Metal Slug X, it drops tanks on you as an attack.
  • Cool Plane: A large gunship with anti-air guns and can carry troops.
  • Clown Car Base: In Metal Slug X, it can carry an unlimited number of tanks on its wings, and replenishes them after it drops them.
  • Flunky Boss: 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.
  • Recurring Boss: It appears as a miniboss in Metal Slug X.
  • Tank Goodness: It's capable of carrying tanks on its wings, and they do attack with their cannons.
  • Weaponized Exhaust: One of its more dangerous attacks is to fire hot exhaust from its jet engines, then sweep the area by moving left and right.

    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.

  • Astonishingly Appropriate Appearance: 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.
  • Mechanical Monster: A giant excavator resembling a cobra that tries to "swallow" the pillar you're on.
  • Macross Missile Massacre: Can fire out a slew of homing missiles.
  • Platform Battle: The player has to jump from platform to platform as it chases them up the large pillar.
  • Reptiles Are Abhorrent: It's a giant cobra excavator mech that's hell-bent on "eating" the player characters.
  • Rise to the Challenge: It'll charge upwards now and then, and as such the player needs to move upwards as well to avoid electrical death.
  • Wave Motion Gun: Charges up a large purple laser that hits the entire middle of the area.

    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.

  • Spider Tank: A tank with four "legs" that allow it to walk or crouch.
  • Fire-Breathing Weapon: Its underside carries a flamethrower.
  • Flunky Boss: It's capable of spawning helicopter firebombs that home in on you and can be destroyed.
  • Gatling Good: Comes equipped with a gatling gun that can fire either small or large bullets.
  • Ground Pound: 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.
  • One-Hit Kill: Getting crushed by it will destroy your Slug and you instantly.

    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.

  • Background Boss: 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.
  • Military Mashup Machine: It's essentially a land battleship on tank treads.
  • Rocket Jump: Surprisingly, you're able to use the explosions from its BFG to boost yourself and get a better shot at it.
  • Tactical Suicide Boss: If it didn't open itself up to expose its huge cannon, it would be functionally invincible.
  • Tank Goodness: A cross between a battleship and a tank.

    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.

  • Abandon Ship: When defeated, Rebel soldiers can be seen jumping out of it and into the sewer water.
  • Down the Drain: 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 below.
  • Shock and Awe: The main turret has an electrical cannon that fires an electrical laser, while it also fires electrical spheres at you.
  • Shows Damage: The sections of its body appear to become increasingly damaged as you fire at those specific sections.
  • Wave Motion Gun: The main turret fires an electrical laser not unlike Tani Oh's cannon.

    Dai-Manji 
The Dai-Manji is much larger than the Mini-UF Os and boasts significantly more armor and firepower. From its bottom hatch, it can send Mini-UF Os (elite mini-UF Os 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.

  • Degraded Boss: In Metal Slug 3, you have to fight them as Giant Mook enemies in the final stage.
  • Death from Above: Has a carpet bombing like attack similar to the Hi-Do, except this one fires indestructible energy bolts.
  • Flunky Boss: Constantly spawns Mars People in flying saucers to harass the player characters.
  • Shock and Awe: Attacks with an aimed electrical laser attack.

    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.

  • Flunky Boss: Constantly spawns Mars People in flying saucers to harass the player characters.
  • Mini-Boss: In Metal Slug 3, you have to fight it as a miniboss in the final stage.
  • Shock and Awe: Attacks with an aimed electrical laser attack from its Dai-Manji attachment.
  • Shout-Out: The way it's defeated in Metal Slug 2/X is obviously a shout out to Independence Day, where an aircraft crashes into a weakspot.
  • Wave Motion Gun: It's capable of firing a huge laser cannon below it.

Metal Slug 3

    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.

  • Advancing Boss of Doom: 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 Turns Red, 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.
  • Giant Enemy Crab: An enormous hermit crab with a tank as its shell.
  • Stealth Pun: It has a huge tank in place of a shell. In other words, it's a tank shell.
  • Tank Goodness: It carries an enormous tank on its back in place of a shell.
  • Weaponized Animal: A huge hermit crab with an enormous tank for its shell.
  • Warm-Up Boss: 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.

    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.

  • Abnormal Ammo: The Ten Commandments attacks by dropping monoliths on the player characters.
  • Crosshair Aware: It targets a player with a green laser before dropping a monolith on them.
  • Cyclops: The Monoeye aliens that protect it all have a single eye.
  • Death from Above: The Ten Commandments' sole attack is to drop monoliths from above that slowly sink into the ground and also act as obstacles.
  • Eye Beams: The Monoeye aliens attack by firing fireball like projectiles from their eyes.
  • Hoist by Their Own Petard: Using the zombie 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.
  • The Monolith: 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).
  • Turns Red: When its health gets low, it starts glowing orange instead of green, and it drops monoliths at a faster rate.
  • The Virus: It's responsible for creating the virus that turned the people in the level into zombies.
  • Wolfpack Boss: 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.
  • Zombie Apocalypse: It's the cause of the zombie virus that has infected several people in the level and possibly the player.

    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.

  • Attack Its Weak Point: It is only vulnerable in the head.
  • Eye Beams: 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.
  • Homing Projectile: The missiles it fires out will home in on the player characters.
  • Improbable Weapon User: 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.
  • Killer Robot: A gigantic and weaponized toy robot.
  • Macross Missile Massacre: Its left arm holds a multi-missile launcher that fires destructible homing missiles.
  • Shock and Awe: Getting hit by its eye beams will electrocute the player character.

    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.

  • Attack Its Weak Point: It's only vulnerable in its Power Crystal, which is very small.
  • Cruel and Unusual Death: Getting hit by its Wave Motion Gun will turn the player character into a rain of coins.
  • Power Crystal: This serves as its weakpoint and also allows it to fire its Flechette Storm attack.
  • Flechette Storm: Fires spiked projectiles of light from its crystal. Yellow ones are aimed at random while red ones are aimed at the player characters.
  • Meaningful Name: Sol Dae Rokker is a play on "Sol De Roca", which means "Sun made of rock" in Spanish.
  • Shaping Your Attacks: One of its attacks consists of summoning ghostly energy wolves that act as explosive projectiles.
  • Turns Red: In both the literal and trope sense. It'll start turning red as it takes damage, and its attacks will also become faster.
  • Wave Motion Gun: It's capable of firing one from its "mouth". Getting hit by it will turn the player into coins.

Metal Slug 4

    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.

  • Background Boss: It assists the Sea Satan by firing missiles at you from the background.
  • Cool Airship: A huge airship constructed by both the Rebels and Amadeus Syndicate, and carries a plethora of weaponry.
  • Sequential Boss: 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.

    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.
  • Sequential Boss: You have to fight five different "floors" of the tower.

    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.

  • Tank Goodness: A modified Iron Nokana that appears to be more tank-like instead of a truck.

    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.

  • Hoist by Their Own Petard: Using the zombie blood vomit can deal incredible damage to it. This is only usable if the player gets zombified by the zombie virus bubbles it drops.
  • The Virus: It releases bubbles filled with the zombie virus.
  • Zombie Apocalypse: It's the cause of the zombie virus that has infected several people in the level and possibly the player.

    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.

  • Gatling Good: Carries a gatling gun that will fire at the player if they're on top of it.

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

  • Load-Bearing Boss: The game's not over once it's defeated, you still have to escape the exploding base.
  • Sequential Boss: You have to fight the Type α Mother Computer, followed by the Type β Mother Computer, and then the main boss.

Metal Slug 5

    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.

  • David vs. Goliath: You can bring the Metal Slug to battle against it where your Slug will be the David and Metal Rear will be the Goliath.
  • Evil Knockoff: 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.
  • Gatling Good: It's armed a gatling gun in the same spot that the Metal Slug has a machine gun in.
  • One-Hit Kill: Getting crushed by it will instantly destroy the slug you're in, as well as you.
  • Shout-Out: It's named after Metal Gear.
  • Tank Goodness: It's essentially a huge version of the Metal Slug that you ride, and comes with all the dangerous weaponry too.

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

  • Bullet Hell: 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.
  • Cool Plane: A gigantic aircraft used by the Ptolemiac Army.
  • David vs. Goliath: 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.
  • Flunky Boss: It's capable of spawning helicopter firebombs that home in on you and can be destroyed.
  • Weaponized Exhaust: One attack used by its rear section has it try to torch the player characters with its exhaust.

    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.

  • Exactly What It Says on the Tin: It's a machine that crawls on building walls.
  • Flunky Boss: Every now and then, the commander will pop out and summon two Ptolemiac soldiers to attack you.
  • Homing Projectile: It's capable of using a homing missile launcher that fires destructible missiles.
  • Glass-Shattering Sound: Uses a sonic cannon to demolish the current floor you're on.
  • Wall Crawl: Like its name suggests, it's fought at the side of a building where it crawls on.

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

Metal Slug 6

    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.

  • Dishing Out Dirt: 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.
  • Military Mashup Machine: A cross between an excavator and a drilling machine.
  • This Is a Drill: It's capable of using its excavator drill to make rocks land on the area, and to attack.

    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.

  • Death from Above: 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.
  • Interesting Situation Duel: You fight on the side of this thing as it slides down a hill.
  • Macross Missile Massacre: Most of its attacks consist of launching several rockets in various patterns at you.

    Brain Robot 
The Brain Robot is a large Invader 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.

  • Advancing Boss of Doom: It'll advance in on the player when it's moving, forcing you to keep moving backwards.
  • Berserk Button: 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.
  • Brain in a Jar: Its head appears to have a huge alien brain within that controls the robot.
  • Car Fu: One of its attacks consists of grabbing a wrecked truck from the sewage and tossing it at you.
  • Energy Ball: Its brain fires these out forwards, which then stop before aiming and flying at the player characters.
  • Killer Robot: It's an alien Brain in a Jar robot that's hell-bent on chasing and killing you.
  • Shock and Awe: 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. It can also fire homing electric orbs at the player.

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

Metal Slug 7/XX

    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.

  • Deadly Disc: 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.
  • Segmented Serpent: Each of the segments are destructible and will help with lessening its firepower.

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

  • Background Boss: 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.
  • Boss Arena Idiocy: 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.
  • Cyber Cyclops: Like its name suggests, it has a single mechanical eye.
  • Detachment Combat: The second battle against it reveals that it can detach its head and torso from its legs, and both are fought as separate enemies.
  • Dishing Out Dirt: Both encounters with it has it capable of grabbing a stalactite from the cave ceiling and dropping it on you.
  • Dual Boss: In Mission 3, its head and arms detaches from its body and you have to fight both of them.
  • Eye Beams: It attacks you with these in its first encounter.
  • Flunky Boss: 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.
  • Giant Enemy Crab: It's a crab-like mecha with the capability of splitting into two, and also has a lot of firepower.
  • Interesting Situation Duel: 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.
  • Macross Missile Massacre: It has a multi-homing missile launcher on its head, which it'll use in its first encounter.
  • Meaningful Name: It's a crab-like robot. It has one eye. Hence, it's a crab cyclops.
  • Not Quite Dead: When defeated in Mission 2, it's seen relatively intact, if powered down. Sure enough, it returns as the boss of Mission 3.
  • Puzzle Boss: 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.
  • Recurring Boss: It's fought as both the second and third boss of the game, except in different situations.
  • Weaponized Exhaust: Its bottom half is capable of using an exhaust cannon during the second time it's fought, once the top half is destroyed.

    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.

  • Ambiguous Situation: It's left ambiguous if it's truly destroyed since it doesn't explode when defeated, instead using a Wave Motion Gun to propel the player characters up to the level endpoint.
  • Flunky Boss: It will often summon two turrets on the waterfall face that fire various types of attack at you.
  • In Case of Boss Fight, Break Glass: Its weakpoint is the glass-looking case in its middle, once its head armor is destroyed.
  • Interesting Situation Duel: You fight it as it climbs up a waterfall, and the platforms you stand on is the boss itself and its arms.
  • Killer Gorilla: A mecha that appears to resemble a gorilla in terms of body shape.
  • Wave Motion Gun: 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.

    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.

  • Attack Its Weak Point: They're only vulnerable in the bright red cores on each of them.
  • Boss Arena Idiocy: 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.
  • Combining Mecha: 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.
  • Death from Above: The Slave Tank is capable of firing several bombs into the air that rain on the player.
  • Flunky Boss: The VTOL can summon elemental pod enemies to attack the player.
  • Gatling Good: The VTOL has a gatling gun attachment on its front side.
  • I Can Still Fight!: 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.
  • In Case of Boss Fight, Break Glass: Their weakpoints appear to be red glass-looking cores.
  • Interesting Situation Duel: The entire fight takes place on the three of them, where your player character uses them as makeshift platforms.
  • Killed Offscreen: 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.
  • Meaningful Name: 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.
  • Shout-Out: 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 RType.
  • Wolfpack Boss: You fight all three of them at the same time.

    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.

  • Duel Boss: 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.
  • Evil Counterpart: It's essentially a rebel army version of the Slug Gigant.
  • Humongous Mecha: It's far larger than most of the pilotable mechs in the series.
  • Macross Missile Massacre: It's equipped with a multi-homing missile launcher on its shoulder and Allen won't hesitate to spam it.
  • Mirror Boss: 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.

    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.

  • Battle Amongst the Flames: 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.
  • Combat Tentacles: 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.
  • Death from Above: The main unit capable of raining fireballs onto you or dropping cylinder grenades from above
  • Gameplay and Story Segregation: 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.
  • Marathon Boss: 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.
  • Sequential Boss: The first phases involve attacking and destroying its tentacles, before you can actually fight the main unit.
  • Shout-Out: Its design appears to be like that of the Trumpet Lillies from In the Hunt.

http://tvtropes.org/pmwiki/pmwiki.php/Characters/MetalSlug