My personal theory as to what TK might have been like before dying and joining the Battlefront. Originally posted (although on the same day) to my AO3 account - Fluffifullness. Thanks for reading!
He is quiet, polite and reserved and just like everyone else. That is the expectation that he first unwittingly created in the people around him, the stage he set for himself, and he plays the part so very well that it probably shouldn't even count as acting. He lives in his role – probably like most people – and he's convinced that he likes it. He's convinced that it's him.
He isn't smart, but he says little enough that it doesn't show. He makes decent grades – great, sometimes – because he spends an appreciable amount of his free time studying. In the occasional in-between hours, he listens to the same music and watches the same TV shows as all of his classmates. He jokes about them with friends, although more often than not he simply listens to and agrees with their opinions. He bases his own ideas upon their words, and no one ever notices. Even if they did, of course, they certainly wouldn't care. He knows, because he may have come from a culture that values individuality but that isn't where he finds himself now.
He keeps his hair meticulously dyed, all the way to the roots – an inky black, and no one bothers to point out how American he looks despite that because to do so would violate another of many unspoken rules. Of course, that doesn't mean that he doesn't know there's no point in hiding it. It simply doesn't keep him from speaking English only as well as the others in his class – and all the time he works to perfect his broken Japanese. He lets his parents brush it off as a natural consequence of moving from so far away – lets them form all their own ideas about him, actually, and then works hard to make it all a new version of reality.
He draws the line at covering up the blue of his eyes – doesn't have any particular reason for that, but his friends all tease him about how obvious it is that the decidedly foreign hue is mean to "attract the babes." That may be the only almost-acknowledgment of his ethnicity that he ever receives, and he considers himself lucky for it.
He hears a few people talk about everyone living behind masks, and he follows his peers every step of the way in mocking the ludicrous concept. His mask runs a bit deeper, after all – deep enough that he can refuse to acknowledge its existence.
Thing is, even the best masks crack. Usually they don't crack where the wearer can see it happen, but he has worn his too long to let it go where others might see it. He's worn it too long not to watch as it breaks away, and he relies too heavily upon it not to paste it back together afterward. He buys a bandana on a whim, one night – no school, and he's wandering the city with his friends. They duck into a little store, just someplace random, and the guys all say it looks pretty cool. That it'd look pretty good on him, and it's cheap.
That's why he buys it.
It's not, however, why he goes home later and stares at himself holding it – in front of a mirror, and the short streamers of soft and bright red dripping like blood from his open palm. It's not why he shakes off the handcuffs of who he pretends to be – and he'd almost forgotten that this wasn't always him – and stops standing still. With an arm raised here and a few flicks of his wrists, he feels like an idiot but he feels better than he has in a very long while.
He feels closer to something, and that's when he ties the bandana behind his head and thinks that maybe – maybe – he can cut loose for now, with no one watching but a long mirror behind closed doors and curtained windows. He can shake off the metal that binds his wrists and split his mask in half with a shard of glass and twisted metal. He can spin – once, twice, on his feet and then practically horizontal on the ground and all of him moving to music he barely remembers. The music he mocks or ignores when he's with other people.
Given another chance at life, he thinks, this is what he'd be. Free of expectations and masks and judgment. He'd say and feel and do as he pleased. He would rebel. He would resist. He'd grow his hair long and blonde and he'd maybe wear those handcuffs around his neck to mock the him that had once worn them properly.
He thinks the same thing as his heart pumps a final burst of inebriation through his system and the wheel beneath someone else's sweaty palms renders metal cardboard and him nothing more than an unwritten book of clichés.
Another chance, he thinks, and that is what he gets.