Newtype - The next step in human evolution, emerging from the genocidal chaos of the One Year War (See Gundam 0080, 0083, 08th Team, F-90 and F-91. These all deal with this particular universe... W is a completely separate series), gifted with supernatural powers of awareness and intuition. They developed with human migration into space, their vast mental powers coming from the need to communicate across the vast distances of space to satiate the needs of the socialite human animal. Basic empathy and telepathic abilities are the staple of the newtype being, enabling them to "sync" with all beings around them, feeling what they're feeling, experiencing what they're experiencing, and in the most extreme of cases, control what they're feeling, experiencing, or even thinking. At their worst, a newtype can actually nullify a victim's higher brain functions all together.
And why do I say that Quatre's a newtype?
(a) He seems to be synced with the other pilots, far in excess to their connection to one another. Examples - He KNEW that Trowa was still alive, even when everyone else (the Professors, his allies, OZ/Romefeller/Treize Faction/etc, the TV viewers) left him for dead... he was confident that Wufei would mystically go against everything in his character-persona and join them to fight as a team... he never seemed all that despondant about Heero after getting over the initial shock of the self-destruct attempt, etc, etc, etc.
(b) His extreme reaction to Heero going "kaboom" points that he IS a newtype, and happened to be synced with the self-destructing twit at that moment (D'oh!).
(c) Just LOOK at the way he breaks Heero out of the Zero system! If you've ever seen anything else in the Gundam Universe and know what a newtype is, that SCREAMS "Hello! Quatre's a newtype!" to you. "It just isn't right to fight," and the friggin' war-mongering soldier of doom agrees?!? Oye.
(d) Ever notice how when Quatre's stressed and focusing on one person, they always, without fail, repeat exactly what he said and think his ideas are the greatest thing since fire and loincloths? (Newtype control, seen in the Gundam 0080/0083/etc series)
(e) Throw newtype into Zero system. Let Zero system enhance newtype powers. Get Quatre stressed. What happens? Wufei... follows... orders... without... question. (Now, is that incredibly out of character, or what?!?)