[[WMG: Infiltration Unit Zeta aka Zee Smith]]
The main character, Zee's origins are explained within the opening paragraph of the main page. He is the de facto hero of the series.
* ActualPacifist: Would only use force to save human life, and only when it was the only option available. He refused to use guns to any degree and though it's implied he was strong enough to kill people, he never did much more than knock them out, if that.
* AIIsACrapshoot: Was programmed to be heartless, emotionless, and a hitman. He ends up becoming a sweet, gentle, loving soul who's a rare male version of FriendToAllLivingThings (although this is sort of the best possible scenario you can have when your A.I. goes awry). [[spoiler:Turns out his creator secretly gave him a MoralityChip in defiance of government orders.]]
* AmnesiacDissonance: Zeta - Memories = Murderous Kill-Bot.
* BadassPacifist: Despite being designed and programmed to be an assassin-bot, he refuses to carry weapons, or ever attack or harm a human being. He faces down an impressive number of foes, including those more than willing to use deadly force on him, his ActionGirl companion, or bystanders, without ever once violating this (excluding the rare occasions where he is under the robot equivalent of MindControl). This is the result of his character development in WesternAnimation/BatmanBeyond, where he started out willing to use force against his enemies.
* ChildrenAreInnocent: Though adult in appearance, he hasn't lived long enough to get jokes, slang, or innuendo, and seems to take people at their word most of the time. He's also a terrible judge of character due to believing the best of people. When he's shape-shifted into child form, even the other kids find him ultra-naive.
* DeadPersonImpersonation: Was programmed to be this way, but his A.I. eventually evolved into an actual personality and he decided he no longer wanted to continue killing and imitating his victims.
* DoesNotLikeGuns: Or any kind of violence, really.
* FriendToAllLivingThings: Even cockroaches. Ro was squicked; squick is a human concept Zeta didn't comprehend.
* HorribleJudgeOfCharacter: Trusts everyone inherently and believes everyone is good deep down. He also can't seem to gauge when people are lying to him, no matter how obvious it is.
* IAmNotAGun: Or in his words, he doesn't wish to destroy anymore. In addition, his statement that "''I'' decide who I want to be" could count as this.
* InnocentInnuendo: Anything that he says that sounds even remotely suggestive is this. He really, really doesn't get it. Special mention goes to kissing a complete stranger and not knowing why Ro was upset.
* NaiveEverygirl: A male version
* NotHelpingYourCase: He's accused of being re-programmed by a terrorist, and no matter what he does the FBI always make it out to be a crime. During most of the series, he was pursuing his creator so he can convince them that he's good, but his actions are taken as an assassination attempt when he accidentally set off the cryogenic chamber, almost killing him. The poor guy just can't win.
* LoveRedeems: The creator has admitted it comes across as ambiguously psuedo-romantic, but it was intended as platonic. It's more his love for the child of the man he's impersonating than the wife that makes him begin to change anyway.
* ScrewTheMoneyIHaveRules: Literally has no reason whatsoever to be as moral and kind as he is other than free will. His morality and heroism are self-enforced standards and as such he cannot be bought off, bribed or threatened.
* TurnedAgainstTheirMasters: A peaceful example.
* WideEyedIdealist: Naive and kind, always taking people at their word, a terrible of judge of character who thinks the best of everyone and generally easily manipulated. It's due to being so young and having no knowledge of the world beforehand, and to be fair, his friends do try to help him get better about this.
* WhyAmITicking: In a crossover episode of ''WesternAnimation/BatmanBeyond'', Mad Stan puts a bomb on oblivious Zeta and sets him loose in Gotham.
[[WMG: Rosalie "Ro" Rowen]]
* ActionGirl: Had her moments
* CloserToEarth: Though the implication is more humans versus robots than women versus men.
* DeadpanSnarker: Constantly.
* ForgottenChildhoodFriend: [[spoiler:Her brother.]]
* NotHelpingYourCase: She's a runaway minor who has a criminal record.
* ParentalAbandonment: Her search for her family is one of the main storylines.
* ProperlyParanoid: In contrast to Zeta's blind trust of everyone, she trusts no one until they prove themselves.
* TrademarkFavoriteFood: Chocolate and the disgusting mixed drink Zeta gives her early on become regular staples; the first is played for humor, the second is less often mentioned.
[[WMG: Agent Bennett]]
* BystanderSyndrome: His response to Batman's plea for help.
* DependingOnTheWriter: Sometimes he's willing to let a known terrorist (Mad Stan from WesternAnimation/BatmanBeyond) run around without diverting his considerable resources to stopping him and saving lives simply because [[BystanderSyndrome it's not his problem]]. Other times he berates West for opening fire in a crowded place, seems genuinely concerned for those around him and goes out of his way to keep people safe. He also varies from being all business to somewhat friendly towards Lee.
* EvenEvilHasStandards: Sometimes. See DependingOnTheWriter above for details.
** He seems to dislike firing in public or on civilians. This cannot be said of all Agents.
* GenerationXerox: His son is a visually identical but highly different personality-wise. Refreshingly, this isn't an issue.
* InspectorJavert: Even though he begins to understand that Zeta isn't as dangerous as he seems. The back cover blurb on the DVD broaches the topic directly: "Just who is the real danger to humanity?"
* MoralityPet: His wife and son.
* NotHelpingYourCase: When he tries to convince his superiors in season 2 he hasn't [[JumpingOffTheSlipperySlope gone insane on this mission]], the fact one of his own Agents left the NSA over his behavior is pointed out. He counters he hasn't had a bad call on his record other than [[WesternAnimation/BatmanBeyond Gotham]], which is not a good incident to bring up since he nearly got part of the city blown up during that incident. [[IdiotHero Agent West]] facepalms audibly in the background.
* ParentsAsPeople: He's an absentee parent, but only because his job's pay is directly in proportion to how many assignments he takes. He and his son have issues about this and resolve it as best they can. His SanitySlippage actually regresses when he's allowed some normal family time.
* PerpetualFrowner: The only time he smiles in the series is at his son.
* PapaWolf: He loves his son. His son is why he takes work so seriously. Therefore his son comes before work and he will pull an EnemyMine to keep his son safe.
* SanitySlippage: Over the course of the series, he begins becoming more confrontational, emotional and callous, leading to more questionable actions. Highlighted by the Mad Stan incident.
** NotSoStoic: He begins to grow increasingly frustrated as the series goes on.
* SurroundedByIdiots: How he views West and some of the NSA, though not Agents Lee or Rush.
[[WMG: Agent Lee]]
* ActionGirl: In contrast to her wimpy partner, Lee was able to hold off a mercenary ''with her hands tied together''.
* AllAsiansKnowMartialArts: Averted. Her fighting style is identical to every other Agent we see in the series. Agent Rush actually has the most kung fu esque moves out of all the Agents, and he's black.
* AwLookTheyReallyDoLoveEachOther: With West. As much as she mocks him, she fights fiercely to rescue him twice in season one alone.
---> '''Agent Lee''': I gotta go save my partner.
* TheCommissionerGordon: Developed into this after Zeta saved her life at great personal risk to himself. Unfortunately, she's not in as much power as most examples, so actually helping him out is hard.
* DarkActionGirl: Before her HeelFaceTurn
* DeadpanSnarker: Usually involving West.
* EqualOpportunityEvil: The she's Chinese, a woman, and ''not'' trained in a stereotypical branch of Hollywood kung fu. PositiveDiscrimination may be at work as she's the OnlySaneMan.
* HeelFaceTurn: Gradually comes to realize Zeta isn't evil. This leads to [[spoiler:her turning Bennett in during the second season after his SanitySlippage becomes too extreme.]]
* LampshadeHanging: Frequently.
* LastNameBasis: It's apparently just Lee, even to her friends.
* NotHelpingYourCase: Goes back and forth: initially she gets this when trying to explain Zeta isn't evil, but she's GenreSavvy enough to try that exactly once and then turn to the much more provable and equally true objection to her superiors that Bennett is becoming unstable. When she feels it isn't taken seriously, she quits, an act extreme enough to prompt investigation into Bennett's behavior. But she can't get Zeta's case heard afterwards when she's viewed as a MoodSwinger who turned on her boss, and any response she has damages her case.
* OddFriendship: Goofy, cocky West and calm, snarky Lee.
* OnlySaneMan: Woman, but still valid.
* SympatheticInspectorAntagonist: Which frequently brings her into conflict with Bennett. Eventually, [[spoiler: she seeks reassignment due to her belief that Zeta is not a threat to anyone.]]
* VagueAge: As per usual with the NSA Agents, we have no clue how old she is.
[[WMG: Agent West]]
* AwLookTheyReallyDoLoveEachOther: He and Agent Lee have this dynamic. "I have to go save my partner," "Don't touch her!" etc.
* BigEater: Other Agents are satisfied with designated meal times and servings. West is never capable of turning down food, even if he just ate.
* BerserkButton: Don't threaten Agent Lee.
* EmbarrassingFirstName: According to the credit, it's Orin. No one ever mentions this due to the Agents being on a LastNameBasis with each other
* LetsGetDangerous: He ''can'' be serious and competent, in a pinch.
* TheLoad: Seen as this by his comrades.
* NotHelpingYourCase: When he's right about where Zeta is at one point, he points out the other times he found Zeta... which everyone knows were either accidents or Agent Lee doing the legwork.
* RecklessSidekick: To Lee and Bennett.
* RedheadedHero: He tries.
* ScreamsLikeALittleGirl: Most notably in "Westbound".
* DarkSkinnedRedhead: Voiced with a vaguely Hispanic accent, too. No one's clear on what this means.
* GettingCrapPastTheRadar: The only reason Bucky's first episode ever got greenlit was because [[DoubleStandard Zeta's a robot.]]
* WhatMeasureIsANonHuman: Doesn't think of Zeta as a person at first.