I Just Want to Be Loved: Naturally, anyone ostracised by society at large nearly their entire lives would be pretty affection-starved. Especially evident when Roxanne first hugs him. See Post Hug Catatonia below.
Longer-Than-Life Sentence: Got 88 consecutive life sentences for his crimes against humanity and Metro City. Largely meaningless, since he's able to waltz out the front door of his Cardboard Prison, and back into his functional laboratory cum lair.
Disappeared Dad: In a weird reversal, Metro Man's parents are hinted to be very uninterested (his father doesn't even look up from his newspaper when he's flying as a baby), while Megamind's "parents" (the prison inmates) treat him warmly like family, despite teaching him Family Unfriendly Aesops.
Genius Bruiser: Played with. In the Prequel comic, Megamind makes their rivalry out as Brains vs. Brawn. Yet his flashback shows that he's not the Dumb Muscle Megamind indicated he was; but even so, his scenes as Music Man seem to hint that he can still be bit of a ditz.
Heroic Fatigue: Metro Man gets so tired of being a hero all the time he fakes his death.
Human Alien: Like Megamind, he's also from a far away planet. Unlike Megamind, aside from the ridiculously buff physique, he looks pretty much human.
Ascended Fanboy: Deconstructed. As a regular human he secretly despises Metro Man because he thinks Roxanne is in love with him. When he gets superpowers he abuses them trying to impress Roxanne and, when rejected, goes on a selfish, childish rampage.
Ax-Crazy: Whenever he gets angry—special note goes to when he discovers Megamind's deception.
Manchild-> Psychopathic Manchild: His reign as Tighten is basically one long, protracted temper tantrum. He also has a clown at his birthday party and generally misses important engagements to play video games.
Silly Rabbit, Idealism Is for Kids!: Roxanne tries talking some sense into Titan, saying that she knows there's still good in him. He simply scoffs at her that she sees good in everyone, even when it's not there.
Spell My Name with an S: Most people still aren't entirely sure if his name is officially spelt Titan or Tighten. While it seems that Megamind originally wanted to spell it as Titan, official printed media such as the "Art of" book, the character poster and the closing credits spell his name as Tighten.
Minion with an F in Evil: He's so pleasant throughout the entire film, that it's highly likely that he went along with Megamind's evil plans less because of being evil and more because it seemed to make his master/friend happy.
Morality Pet: Played with. He's much nicer, friendlier, and more helpful than Megamind, but in his devotion Minion not only does nothing to stop him from being a villain, he becomes upset when Megamind suggests that they not be evil anymore.
Yes-Man: As described by the filmmakers: "He might suggest that jumping off a building isn't the best idea, but in the end, he wouldn't stop (Megamind); he would just race to the bottom and build a net."