Contact Info~ In the beginning there was a person. He might have been a good person, and he might have been a bad person. Or perhaps he simply was a person. Regardless, his heart was taken from him, leaving a wandering body and soul. A nobody calling himself Demyx in the place of that somebody.
Nobodies are what's left of a person when they lose their heart. Without darkness or light in them, they should not exist according to the laws of the universe, but insist on doing so. Despite his lack of battle finesse, Demyx had an exceptionally strong heart when he had one, and thus was able to maintain a human form similar to the one he previously held while those with weaker hearts become smaller, less humanoid. This is all that's really required to be a member of the Organization XIII.
With Demyx's happy-go-lucky (if exceptionally bipolar) attitude it's hard to imagine that he could have ever been a bad person. Alternately, if the theory is correct in that the Nobodies are what was left of the Somebody's heart that they weren't using, Demyx might have been the worst of the lot to begin with. He remembers when he was Somebody, clings to the memory of a heart and what it was like, though it's no doubt been tainted from reality by dreams at this point. Demyx is both the most well-adjusted member of the Organization XIII and least well-adjusted. He's friendly and personable and (if a bit annoying) a blast to be around. He's also severely disconnected with the reality of his situation, sometimes claiming to have a heart after all. He can be pushed to drop his clinging to memories of emotions, switching suddenly to the emotionless being capable of extreme violence that they claim all Nobodies truly are.
All the same, Demyx tries to be happy and nice and friendly. Like all the members of Organization XIII, Demyx controls a sub-type of Nobody. His are the Dancers - the only visibly female (or at least appearing to be) kind of Nobodies. Quick and lithe, they're a bitch to fight in high numbers. Demyx treats his Dancers with kindness, and they have as much affection for Demyx as heartless beings are capable of having.
Demyx's talents involve areas other than combat. He's passable in a fight, but also a coward (or tries to maintain the illusion of being one). His control of water-magic is superb, but his real talent is with music, as evidence that his 'weapon' is in fact a sitar when you get right down to it. He uses the music to control the water, but also plays just for the joy of making music. He is also a fantastic dancer.
P H Y S I C A L L Y Demyx is about 5'10", tall thin. He's got dirty blond hair in a style that can be best described as the bastard child of a faux hawk and a mullet. Unless otherwise noted, he is always dressed in his uniform, the Organization XIII coat, which is black and leather-like covering from wrist to mid-calve. The hood is deep and with it up, his face is completely covered. To supplement the open parts of the coat he's got black pants of the same material, black boots that go up to his knees, and black gloves of the same sort-of-but-not-quite-leather that go almost up to the elbows. He's got turquoise eyes and a light tenor voice, appearing somewhere between 19 and 21.
A note to psychics and anyone else with extrasensory perceptions both technical and magical: Demyx is a Nobody. He has no heart, physical or metaphysical, and by rights should not be, even in his home canon. If you try to read his emotions you get nothing - not even the nothing of a sociopath or truly zen person - there's just dead air where a person should be. Sensors show up a being that clearly does exist yet should not.
A S O F 1 0 / 3 1 / 2 0 0 8 . . . Demyx has a heart. He is, however, not human. He's still made significantly of his element, and thus has way too much blood to be human (for one example). However, it is a very real heart, making him 'human enough'.