A geneticist with a past even she's not completely sure of, Naomi was chosen to support Snake during the Shadow Moses mission to provide feedback on the Genome Soldiers. She had her own agendas, which included injecting Snake with the biological weapon FOXDIE to kill the FOXHOUND members, which would then kill Snake himself later. It turns out she did it because she was Gray Fox's adopted sister and she wanted revenge (although Liquid also mentions that the Pentagon ordering her to do so had something to do with it).
Naomi returns and redeems herself in the fourth game where she helps Old Snake deal with Liquid Ocelot and forms a close relationship with Hal and Sunny.
Inconsistent Dub: In the original English version of Metal Gear Solid, Naomi was given a vaguely British sounding accent. When the dialogue was redubbed for the GameCube remake, Naomi was given a more neutral accent which was also used for Metal Gear Solid 4. Actually, she's from Rhodesia/Zimbabwe.*
which was originally a British colony before they declared independence during the Cold War.
Ironic Hell: Her tampering with the FOXDIE virus injected into Snake to have a wildcard activation to which even she won't know when it will activate, in revenge for Snake indirectly subjugating her brother, Gray Fox, through the Cyborg Ninja project / gene therapy project, ironically saves Snake from the intended fate of being killed by FOXDIE at the end of the mission. The Patriots also took note of this, as they had her imprisoned for doing that action.
Just Following Orders / Not In This For Your Revolution: The other reason for injecting Snake with FOXDIE was because the Pentagon ordered her to, as they wanted a way to both get rid of the Sons of Big Boss, and at the same time retrieve REX and the Genome bodies without risk of them being damaged. Of course, her listing Snake as one of the targets of the virus, or at the very least modifying the virus to activate as a wildcard value in Snake's case, was certainly not done under their orders or even the Patriots orders.
Known Only by Their Nickname: It is strongly implied that she is not actually named "Naomi Hunter" (Miller/Liquid mentioned that she stole the identity papers of the "Real Naomi Hunter" at one point). Likewise, even she doesn't know her real name.
A girl on Snake's Mission Control, she is a teenage prodigy and tech wiz who developed the Soliton Radar and Codec. She frequently quotes proverbs to lift Snake's spirits up. She later becomes a Naval officer in the fourth game.
Chinese Girl: Though she may or may not have an accent depending on which dub you're playing. MGS1 and MGS2 feature the lisping and problematic relationship with the letter "r." She speaks normally in the other sequels.
Gadgeteer Genius / Teen Genius: In the original MGS. However, the codec conversations in Sons of Liberty imply she's been pirating technology from the Pentagon. Snake gruffly warns Mei Ling to cut it out before she gets caught.
Not Even Bothering with the Accent: Although she does have a legitimate, if not slightly exaggerated Chinese accent, it's at odds with the fact that she was actually born and raised in America. Like Naomi, Mei Ling drops the accent altogether in Twin Snakes; this became canon in time for Metal Gear Solid 4.
Blood Knight: Most of the FOXHOUND members, or at least Vulcan Raven and Liquid Snake, qualify as such.
Dangerously Genre Savvy: Liquid Snake and the rest of the FOXHOUND members heavily anticipated that Snake would be deployed to Shadow Moses Island, and even anticipated the likelihood that he'd be secretly monitored by the Patriots, so they continued acting as though they actually had all codes even when Snake was unconscious or offscreen until Snake unwittingly activated REX for them. In fact, even the one time Liquid potentially messed up in regards to his identity (citing things that "Miller" shouldn't know from being holed up in Alaska), it was clear that even if they managed to find out that Miller was actually dead by that time, it would be far too late to stop his plans.
Dysfunction Junction: Liquid's combination of Well Done Son Guyism and homicidal resentment towards his father, Wolf's tragic past and Stalker with a Crush tendencies towards people she intends to kill, Ocelot's torture fetish, Mantis' violent misanthropy... Raven comes across as the most stable of the lot (at least of the members who get in-game character development), and he's an unapologetic Blood Knight.
Equal-Opportunity Evil: Consists of an old Russian gunslinger, an asexual Russian psychic, a university-educated Native Alaskan shaman/heavy weapons enthusiast, an indestructible British-American cloned super warrior, a female Kurdish sniper, and Decoy Octopus.
The leader of FOXHOUND and Shadow Moses Island, Liquid is the second of the "Sons of Big Boss" introduced. He has a major complex about Solid Snake, and was told for his entire life that he inherited Big Boss' recessive genes in order that Solid Snake could get the dominant ones, when in fact the reverse was true. Word Of God says he isn't naturally blond.
Though at least some of this might be because he just needs to explain it better.
Also in Metal Gear Solid 2, it is revealed by Emma Emmerich that The Patriots have spread much false information throughout society, including on biology. Considering that Liquid's childhood was highly influenced by the Patriots, he probably was outright lied to about biology.
Calling the Old Man Out: He hates Big Boss because he thinks Big Boss knowingly made him the inferior one during the Les Enfants Terribles project, and he implies that one of the main reasons for wanting to continue Big Boss's dream of a world of conflict is so he would further tarnish Big Boss's reputation ("Now I'll finish the work that father began. I will surpass him...I will destroy him!")
The Chessmaster: Of the Shadow Moses incident, although later games would reveal him as The Pawn in the bigger scheme of things.
Child Soldier: He was raised within the British Military, and assuming what the Official Missions Handbook stated about him is canon, he may have done some mercenary work as early as Age 13.
The Determinator. The only Metal Gear villain Snake was unable to defeat, despite several temporary wins. He just will, not, die. It takes a biological WMD to kill him.
Disney Villain Death: Averted. At one point when fighting Snake, he fights him on top of the ruined Metal Gear REX mech, a mech that is over ten meters and to which he claimed that the fall would kill even Solid Snake. Despite being knocked off the mech, he still manages to survive and drive a Jeep, chasing Snake.
Engineered Public Confession: Subverted in Nastasha Romanenko's novel. He (and presumably the other terrorists) actually knew all along that they had planted a radio bug on Snake and was recording everything he and his soldiers were stating, and his codec calls, but allowed for it to happen anyways.
Evil Brit: Liquid was given to the British government as an infant and was raised as a national.
Evil Counterpart: Although he was the definite villain in the game, it was also implied to be inverted, as Psycho Mantis remarked that Solid Snake was actually worse than Liquid in his dying speech.
Evil Twin: Though Psycho Mantis has implied that Solid Snake may actually be the true Evil Twin. Liquid is fighting for a cause, the restoration of Outer Heaven. Snake is fighting because he, on a subconcious level, needs war to feel alive. Although he later finds other reasons to keep on living.
Great White Hunter: Liquid, an Englishman through and though, enjoys fox hunting as a sport. When assigned to the middle east (where no foxes or hounds were forthcoming), he substituted it with hunting jackals and using royal harriers.
The Heavy: The last quarter of Solid is one long battle between Snake and Liquid. Even before that, he was in radio contact with Snake for the entire game disguised as Master Miller.
He Who Must Not Be Named: According to Campbell, Liquid's real name was highly classified to the extent that not even someone within the highest ranks of the military (such as himself) are allowed to know it.
Improbable Piloting Skills: He was fully capable of piloting a Hind D in the middle of a blizzard as well as shooting down two F-16s arriving from the Galena Air Force Base, and also pilot it while operating the weapons operator seat.
Light Is Not Good / Dark Is Evil: Liquid referred to himself and Snake as "the brother of light" and "the brother of dark", although of whom he was specifically referring to in regards to the titles is never actually specified.
Master of Disguise: Strongly implied to be such, seeing how he effectively disguised himself as Master Miller after arranging for the latter's death.
Meaningful Name: The very definition of "liquid" is "an unstable substance that has no constant shape or structure". When you compare Liquid Snake's personality to that of Solid Snake, his twin, this makes perfect sense. Compared to Snake (who has his flaws, but stays loyal to his friends and has a constant set of values) Liquid is a dangerously unstable figure without any permanent ideals or goals beyond wreaking havoc on a world that wronged him and finding his place in a world of unending war.
Military Brat: Was the clone of Big Boss as well as raised within the British Military, as implied in Peace Walker.
My Hair Came Out Blond: According to Yoji Shinkawa, Liquid Snake was originally dark-haired, just like Solid Snake. However, it ended up bleached to blond as a consequence of his time as a Prisoner of War, because of the sun's intense rays within the Iraqi desert. Interestingly, Solid Snake was originally going to be a natural blond, too; hence his lighter hair color in the briefing videos.
Nietzsche Wannabe: Liquid Snake figures that he might as well do what his genes tell him, since otherwise, he's nothing. Justified, in that there's little else he ever had other than war, being created for the purpose of it.
Not So Different: Liquid gave this spiel on top of Metal Gear REX, though Snake rejected the notion that he's just a born killer. However, Liquid's words have definitely stuck with him; one of the trophies in MGS4 is acquired by gunning down 100 mooks; Liquid's mocking laughter and echo, "You enjoy all the killing!", causes a guilt-ridden Snake to vomit.
Psychopathic Manchild: Assuming Ocelot's fake possession portrayal of Liquid is valid, Liquid seems to qualify under this trope.
Psycho Prototype: Although it is heavily implied that Liquid Snake was created first, and the superior genes were used from him to create Solid Snake, The Stinger subverts this by revealing that he had the superior genes all along.
Rasputinian Death: He survived having his Hind D shot down by Solid Snake, being hit with multiple Stinger missiles, being caught directly within the explosion of Metal Gear REX, surviving a four story fall from Metal Gear REX, was hit with several bullets by a turreted machine gun onboard a Jeep, was caught within a Jeep crash, and he was still ticking up until he succumbed to FOXDIE. Even then, with the last one, he lasted longer against it in the remake, initially collapsing out of agony, but then attempting to grab Snake twice before staring him down and finally passing away, in what was about a few minutes. Only his father and Vamp surpassed him.
Self-Made Orphan: Kind of. Although he never actually killed Big Boss, nor was Big Boss actually dead, anyway, Liquid Snake made it very clear in his Motive Rant that he certainly would have murdered Big Boss himself had Solid Snake not done the deed himself, and in fact hated Snake partially because Snake "stole that chance."
Social Darwinist: He believes that peoples' genes are all that matter in regards to fate or their future. Ironically, this actually has little to do with his actual plot (it was closer to a Warriors Heaven.)
Woobie, Destroyer of Worlds: The Metal Gear Solid 4 novelization, along with the Official Missions Handbook expands a lot on Liquid Snake's background: He basically was sent into Iraq before the advent of the Iraq War, for the sake of Britain as a sleeper agent to organize various insurgencies in Iraq, and also located several things thanks to connections he made with insurgents against Saddam Hussein's government. However, just as he was to act on destroying the SCUD missile launchers (at least 4 were destroyed by this time), he ended up captured by Iraqi paratroopers belonging to al-Amn al-'Amm secret police, with the strong implication that the SIS sold him out for a more valuable source of information from within Saddam's inner circle, leaving him to be heavily tortured and brainwashed, which evidentially led to his Humans Are Bastards viewpoint in the first game. Just when he was getting his act together by the time he started leading FOXHOUND, Ocelot had to reveal to him that he was a LET clone, causing him to sink real low in anger and self-loathing and transform him into the character we see from Solid onward. Honestly, who can blame him for the stuff he pulled after knowing that?
Xanatos Speed Chess: A large part of his Evil Plot was actually improvised by Psycho Mantis, since acquiring the PAL code from Baker and Anderson failed due to the latter dying under a supposedly botched torture session courtesy of Ocelot before he could divulge it.
He and his pack of Elite Mooks, the Ocelot Unit, wear the red/maroon berets of the Spetznaz GRU, the black combat uniform of the Naval Infantry, the black telnyashka (striped shirt) of the Russian Navy, and the knee-high black leather officer's boots (opposed to the trooper's boots used by KGB and GRU). It seems Major Ocelot has a lot of leeway with putting together his unit.
Badass Normal: He's a regular human in a world of cyborgs and giant robots.
Bizarre and Improbable Ballistics: The 'Master of Ricochet.' Ocelot can somehow bounce his bullets off walls and other objects to go exactly where he wants. The trick to beating him is to not reveal your location; if he sees you duck and cover, it's all over.
Book Ends: Ocelot is the first and last boss of the "Solid Snake Saga".
Boomerang Bigot: Comments "I never trust a Frenchman!" Even though he was born in Normandy, France.
Breakout Villain: Very few people who finished the first Metal Gear Solid when it came out expected him to be anything more than Solidus Snake's lackey in the sequel.
Cats Are Mean: This is more evident in Snake Eater, where Young Ocelot imitates an ocelot's growl to summon his men. About the nicest thing you can say for Ocelot is that he believes in a fair fight, as jungle cats "prefer to hunt alone." Needless to say, this stands in contrast to Big Boss/Snake's fondness for dogs.
The Dog Bites Back: He had backstabbing tendencies as early as Metal Gear Solid, but his technical first time at genuinely backstabbing someone (disobeying Volgin's command to gun down Naked Snake during the final battle) was closer to this trope given the abuse he had to endure under Volgin. Even if his serving Volgin was technically a ruse to begin with.
Double Agent: In Solid. It wasn't until Sons of Liberty that he became a...
Double Reverse Quadruple Agent: Over the course of the series he's worked for CIA, NSA, KGB, GRU, Colonel Volgin, FOXHOUND, rogue FOXHOUND, Colonel Gurlukuvich, Solidus Snake and the Patriots while not really working for any of them. Metal Gear Solid 4 reveals his true allegiance was to Big Boss ever since MGS3.
The Dragon: To Liquid, Solidus and Volgin respectively in the first three games.
Dragon Ascendant: He's the Big Bad in the fourth game, with Vamp as his Dragon. Everything that we see him do from the first Solid onwards is his attempts to destroy the Patriots and fulfill Big Boss's wishes.
Dystopia Justifies the Means: He is said to have applauded Big Boss' vision of a strife-ridden world, likening it to his own favorite era: the wild west. As stated in Metal Gear Solid and its remake, The Twin Snakes*
The player has to survive the third torture round without submitting to learn it
, was that he believes that, in a world filled with war, people at least could express their true emotions and personality, especially when the current age prevents them from doing so.
The Gunfighter Wannabe: Throughout MGS3, he always tries a little bit too hard to impress people with tricks like spinning and juggling revolvers, and usually gets slapped down for it.
Gun Twirling: It has practical applications too: Young Ocelot uses this skill to survive an onslaught of The Pain's hornets.
I Fight for the Strongest Side: Big Boss and his progeny are the only people Ocelot truly respects. He is the only character in the series to interact with all four.
I Love the Smell of X in the Morning: Pretty much everything associated with revolvers gets him aroused. He comments on the smell of cordite ("Y'know, that sulfury smell?") during his duel on Shadow Moses.
Implacable Man: In regards to his actions in MGS3, he is this trope incarnate.
In Love with Your Carnage: Ocelot's pseudo-romantic admiration for Big Boss when he hears about Big Boss managing to kill people so easily.
Maybe Magic, Maybe Mundane: It is stated that Ocelot began his "Liquid Ocelot" ruse as far back as when he had Liquid's actual arm attached (ie. MGS2's Tanker and Big Shell incidents) but he replaces it for a synthetic arm in the intervening time between 2 and 4 because the initial transplant was unstable and affected his psyche. The implications of this and the apparent cause of instability are left vague.
Multiple-Choice Past: Naomi mentioned that, according to his official case file, after the fall of the Soviet Union, he briefly worked as a member of the Russian Tax Police, OMOR, and the successor unit to the KGB, but left due to not liking the rigid rules. However, the Metal Gear Solid 4 database indicates that the case file was actually falsified to cover up his alliegance to the Patriots.
Also, in Metal Gear Solid 3, EVA explains in a radio conversation that she was told by Volgin that Volgin apparently raised Ocelot within GRU ever since the Philosophers kidnapped him during the Battle of Normandy after his birth. However, seeing how his codename was ADAM, and thus worked with the NSA in the past before "defecting" to the Soviet Union, and was also implied to be an agent of the CIA as well, its unlikely that Volgin's account is true at all, unless Volgin meant it figuratively.
Ocelot: He's good. Volgin: Fallen for him, have you?
He expressed an interest in both Sniper Wolf and Meryl in MGS1, but soon jettisoned the Dirty Old Man part of his character makeup. In fact, he was outwardly repulsed by EVA's ridiculous perfume and breast implants.
Start of Darkness: Word Of God states that Big Boss's enduring Volgin's torture is the reason why Ocelot became a torture fanatic, since beforehand, he held distaste for torture.
FOXHOUND's psychic member, Psycho Mantis was driven insane when he went to deep into a psychopath's mind. Famous for reading the player's memory card and commenting on the games saved on it. A character resembling a young Mantis is shown terrorizing Big Boss with hallucinations in Metal Gear Solid 5's trailer.
Asexuality: Psycho Mantis has a particular distaste for the biologically universal "need for breed."
Ax Crazy: Of all the members of Liquid's FOXHOUND unit, Mantis was shown to be the most insane and depraved.
Compelling Voice: It is implied that this is how Psycho Mantis applies his psychic abilities to place people under mind control (as his theme "Mantis' Hymn" often plays in the background of Meryl being brainwashed by Mantis, with Naomi also referring to it as his "mind control music").
Crucified Hero Shot: Inverted. Some official artworks as well as a certain attack of his have him in a pose similar to that of Jesus's crucifixion, and he's a villain.
Death Equals Redemption: It's subtle, but his last words are very effective at conveying how different Mantis might have turned out.
"This is the first time I've ever used my power to help someone. It's strange... it feels... kinda... nice."
For the Evulz: He reveals that he joined Liquid's little coup just to kill as many people as possible during his death speech.
Go Mad from the Revelation: Twice. The first as a boy, when he read his father's mind and found that he hated the young Mantis, possibly enough to want to kill him, leading Mantis to psychically destroy his village. The second was during his stint in the FBI, when he went too deep into the mind of a serial killer, causing Mantis to adopt said killer's personality.
Hoist by His Own Petard: Snake's first-person view is replaced by Mantis' line of sight during their battle. If you failed to pick up the thermal goggles, you can easily discern his position by using this.
House of Broken Mirrors: The office where Mantis is lurking has a smashed mirror, plus numerous marble busts with duct tape covering their faces (mirroring Mantis' own). In the Twin Snakes update, he uses his mental powers to distort even the wall photos.
Meaningful Name: The "Psycho" part of his codename has two meanings: One is in reference to his psychic abilities. The other is also short for "Psychopath" or "Psychotic", referring to Mantis' evident insanity.
Mind Over Matter: His projectiles aren't a big threat. The worst obstacles are the office decorations he flings at you: somersaulting chairs, marble statues buzzing around Mantis' body, and even flying deer antlers.
Woobie, Destroyer of Worlds: He saw little point in the "selfish desire of passing their genes on." The (questionably canon) Official Missions Handbook seems to heighten his stance, where it claims that he actually wants to end up dying because a parasite (a byproduct of those with genuine psychic powers) was making him do bad things despite his best efforts to control it, because when he is dying, it will be gone, and then he'll at least briefly experience a peace in mind.
Friend to All Living Things: The wolves are trained to recognize Sniper Wolf by scent. Wearing her handkerchief causes them to wag their tails happily, even around Snake!
Functional Addict: She's addicted to diazapam, the same pills Snake injests to reduce hand tremors while aiming. Creepy. This is a side-effect of Wolf's refusal to switch shifts with a backup sniper. On the upside, her constant intake of tranquilizers seemed to suppress FOXDIE, if not outright neutralize it.
In Love with the Mark: A rather twisted version, as Sniper Wolf becomes so obsessed with her targets that they are literally all she thinks about, to the point where she's said to fall in love with them... right before she puts a bullet through them anyway.
Loves the Sound of Screaming: Kind of. She explains during her death speech that her lullabies were gunfire, sirens, and screaming; although the context it was given since she was actually born and raised during a time where her people, the Kurds, were being exterminated in Iraq, indicates that she was most likely meaning this literally.
Pet the Dog: Literally. And then there was the matter with Otacon.
Reincarnation: Otacon seems to think Wolf is still haunting Shadow Moses. In MGS4, Crying Wolf is killed in the same spot where Sniper Wolf died. A wolf scoops up her body and disappears into the woods; the game implies this is the spirit of Sniper Wolf.
Shout Out: According to Kojima, the scene where Sniper Wolf riddles Meryl with rounds from a sniper rifle was based on Full Metal Jacket. Similarly, one of her lines ("Well I'm going to send you a love letter, my dear.") was a direct lift from Blue Velvet.
Straw Feminist: Wolf holds a few misandrist views, claiming that women made better soldiers than men. She taunts Solid Snake for being an example of men who "can never finish what [they] start," as well as boasting that two thirds of the world's greatest assassins are women.
FOXHOUND's shaman. He first fights Solid Snake in a tank, then in cold storage with a minigun.
Adaptation Expansion: His character is heavily expanded on in the MGS comic, him being the one who informs Liquid of the deaths of Mantis and Wolf, and giving away the secret of FOXDIE, along with some scope of Liquid's plot during his confrontation against Snake, as opposed to his simple hint in the game.
FOXHOUND's impersonation expert. Solid Snake never actually sees what he looks like in-game, though a brief flashback shows Raven pulling off his mask. Instead Snake sees him when he is impersonating Donald Anderson, and he dies shortly after.
Lost In Character Octopus originally worked in Hollywood as an actor and SFX artist. Afterwards, he was recruited by the CIA for his exceptional skills in mimicry.
Master of Disguise: When impersonating someone, he will even go so far as to substitute his blood for their own. However, this is likely due to the fact most of his high-value targets carry nanomachines. Using the DARPA Chief's blood, Octopus was able to appear on Snake's soliton radar.
Polyglot: Octopus was fluent in a dozen languages.
Red Right Hand: Octopus can't alter the size of his skull, but did elect to have his ears surgically removed. He also had his hairline, cheekbones, jaw, and nasal bones shaved down, to make disguising himself easier, and has a voice synthesizer implanted in his throat.
The niece of Roy Campbell (later revealed to actually be his daughter), Meryl always dreamt of being in the military and living up to her heroes in FOXHOUND, but proves to be less than competent.
She later makes a comeback in MGS4, a lot more competent and tougher.
Amazonian Beauty: Meryl is a lot sturdier looking by MGS4, compared to her appearance in Metal Gear Solid. When you see her in her wedding dress, her arms are very noticeable... especially when she arm wrestles one of her teammates.
Cry Cute: In the ending of Act 1, after Ocelot's attempt at shutting down/hijacking the SOP system failed due to his using the wrong DNA (It Makes Sense in Context), Meryl is seen breaking down into tears due to her suppressed emotions being unexpectedly released from the lockdown, strongly suggesting that, although she is certainly not a rookie anymore, she certainly hasn't gotten over her sorrow and reluctance to fire a weapon at living targets.
Daddy's Girl: Averted, her legal father died while she was very young, and she never actually knew that her birthfather was actually her uncle until after the events of Metal Gear Solid. Even after that, Meryl ends up having an estranged, non-talking relationship with her father both because he married a brunette woman who was young enough to be his daughter by the time of Metal Gear Solid 4 (not knowing that the marriage was actually a sham to protect the woman and her kid from the Patriots, as they won't use them as leverage for Raiden) and from the fact that she was conceived by her uncle in an extra-marital affair with her mom that she learned from Roy Campbell. It wasn't until the ending where Meryl marries Johnny Sasaki/Akiba that she and Campbell even start having a decent conversation.
Faux Action Girl: A deconstruction of it in the first game. She badly wants to be an Action Girl, but she's completely inexperienced and in over her head, and has has her illusions destroyed when she learns that War Is Hell.
Heroic Bastard: Meryl Silverburgh was conceived in an extramarital affair between her uncle, Roy Campbell, and her mother. It's also hinted that this is one of the reasons for her sore relations with her father in MGS4.
Ms. Fanservice: In MGS. In addition to her being rather cute, a lot of emphasis is put on her rump (which actually becomes a plot point in the game when you have to identify her distinct hip-shaking walk when she's in disguise) and she even gets a couple scenes in her underwear.
The Other Darrin: An interesting variation: In the English version of Snake Tales in Metal Gear Solid 2 Sons Of Liberty, she's "voiced" by Vanessa Marshall, because her "voice" was actually reused voice clips of Olga Gurlukovich. In the Japanese version, it makes a bit more sense, as Olga and Meryl shared the same voice actress.
An Anime fanboy (so much so that his codename is based off an anime convention) Otacon is the designer of Metal Gear Rex, though he had no idea it was going to be used to launch nukes. After learning the truth, he vows to help Snake stop Metal Gear at all costs, and really becomes an Ascended Fanboy.
Actor Allusion: Not in the series itself, but in Super Smash Bros. Brawl, if using the Codec when fighting Captain Falcon at Shadow Moses, Otacon and Snake will reveal that they are both fans of the character. In the Japanese version of F-Zero's anime adaptation (Falcon Densetsu), Captain Falcon is voiced by Hideyuki Tanaka, who voices Otacon here.
Ambiguous Disorder: He's socially awkward, rather Literal-Minded (see the Chinese Proverbs in MGS 2), obsessive about his interests, and often doesn't seem to have much understanding of other people's motivations.
Ditzy Genius: Particularly in his first appearance. He's a brilliant engineer, but rather clueless about the realities of his situation and the people around him. He gets a bit savvier in later games, although he's still rather quirky.
Hollywood Nerd: An interesting case of this: in the original game, he looked very much a nerd with messy hair and a weak deposition. In Sons of Liberty, he was designed a bit tougher, and his Character Development showed through. In Guns of the Patriots, Otacon becomes a full-out Hot Scientist who gets it on with Naomi.
Ink Suit Actor: Kind of: He wasn't actually portrayed by series creator Hideo Kojima, but his overall design as well as certain mannerisms of Otacon in Metal Gear Solid 2 were based directly on him, if the Director's Commentary was anything to go by.
Likes Older Women: This is not something he would be proud of as it is a very tragic experience for him. He was seduced by his step-mother and his father caught him in the act and committed suicide by drowning himself in the pool. Unfortunately, he accidentally dragged Emma along with him, causing her hydrophobia.
Lovable Nerd: And an effective foil against Snake's gruff hyper competence.
Not What I Signed On For: He helped develop REX thinking it was a defense weapon, and out of a desire to make an actual mecha from animes. The guys who hired him conveniently left out the fact that the weapon he developed was actually a WMD.
Playful Hacker: Otacon has a habit of sneaking code into REX that his employer specifically forbid him to. In addition to REX's weakpoint (a "character flaw" to give it personality), Otacon also implemented a program to make REX fight like a boxer, using its own body as a weapon. The suits didn't approve of risking Metal Gear's delicate sensors, but the program is still in there, as Snake discovers in MGS4.
Johnny first appears in Metal Gear Solid as a guard with stomach problems whom Meryl strips and uses his clothes for her escape. His grandfather also served as a guard during the Cold War.
In Guns of the Patriots, he becomes a member of Meryl's Rat Patrol 01. He loved Meryl ever since she stripped him in Shadow Moses, and ends up marrying her after admitting his love for her.
Afraid of Needles: The explanation Johnny gives when revealing why he doesn't have any nanomachines in his body.
Amazon Chaser: Meryl's action girl status certainly seems to be a plus for Johnny.
Former president of Arms Tech, the developer of Metal Gear REX. Solid Snake tries to rescue Baker after he is taken hostage in Shadow Moses, but Baker is killed by the FOXDIE virus before he can divulge any information about REX.
Asshole Victim: Probably: The ability to have the stealth nuke on a railgun on REX to basically break retaliation theory is strongly implied to have been Baker's idea, and if the alluded to rumors of Boorda's true cause of death and the timing of the death and REX's development is anything to go by, he may have also had Boorda killed specifically because he wasn't able to get into the pentagon's black budget before Boorda.
Corrupt Corporate Executive: Though he's no more corrupt than any of the other arms dealers bribing Congress. He's really just trying to save his company, which is in danger of going bankrupt.
The Stool Pigeon: Lacerated Larry Type: He divulged his half of the PAL code from having his arm broken by Ocelot, as he wasn't trained in physical interrogation. He was the only one to divulge his code, as Anderson died before he could divulge the other half thanks to Ocelot.
Well-Intentioned Extremist: He developed REX as a means to keep his company from going under as a result of SDI, and his loss of the Generation X fighter plane to another stealth manufacturing company.
Commonly known as the Genome Soldiers, they are soldiers enhanced genetically that rebelled and joined up with FOXHOUND. They come in four main variants: arctic warfare, light infantry, NBC warfare and Heavily Armed Troops.
Brainwashed and Crazy/More than Mind Control: Several of the Genome Soldiers were brainwashed into participating by Psycho Mantis, although Liquid's specific words imply that he more or less gave them a morale boost.
Elite Mook: The Heavily Armed Troops unit, which explicitly established to be former Outer Heaven mercenaries.
Genius Bruiser/Informed Ability: According to Naomi and Campbell, the Genome Soldiers, in addition to being skilled warriors, also have an IQ of 180. However, its hard to believe that they possess such intelligence when they end up missing Snake a few times.
The Guards Must Be Crazy: Despite being intelligent soldiers, they apparently fail in spotting Snake even when he's only a few yards away from their line of vision. Probably justified regarding the outdoor soldiers, at least, since there was a blizzard at the time of the mission, which would cause a poor amount of visibility on their end. That's also not getting into the implication that they deliberately avoided spotting Snake in order to trick Snake into activating REX.
The Goomba: The Arctic Warfare variants are the first one to appear, but the Light Infantry soldiers are actually much more common and weaker.
Mascot Mook: The Arctic Warfare soldiers are used to represent the first MGS in Portable Ops Plus.
Super Soldier: They were genetically enhanced with Big Boss's soldier genes.
Flawed Prototype: Every single one of the soldiers ended up undergoing an illness thanks to their having asymmetry theory. That's also not going into the Gulf War, where the Gulf War Syndrome and the Gulf War Babies that resulted in it were apparently side-effects of the procedure.