Treter is congenitally blind and spirit-blind. In this culture everyone has a kind of low-level connection to a 'universal' 'life force' called the Spirit. It means they can sense things like gods, unusual changes in something's 'life force', etc. This connection is achieved through a feature of their brains, in effect like a second personality (or Pullmanesque daemon) - these actually have names, though they are not recognised as independent entities and the name functions more like a middle name or surname.
Treter, being half-and-half, has no such connection and is thus incapable of even basic spiritual senses. In addition, the lack of the connecting feature resulted in learning and behavioural difficulties during Treter's childhood. Dyslexia and ADD, roughly.
Coming from a species bearing cursory resemblance to humans with little or nothing in common genetically, the odds against Treter's conception, birth and survival were immense. Intervention on the part of a certain goddess is suspected. Nobody has any clue whether Treter has inherited any connection to her. (OOCly, Mutt says he hasn't; of course, the deity may begin to notice him if he ever runs into his father...)
Silver hair - a little ethereal, at that - is quite normal in Treter's mother's people. Their skin tends to be firm, flexible and rubbery and does not wrinkle or become damaged from long exposure to water. Treter's nose averaged out between his mother's flattish one and elfin pointiness. He has a fairly pronounced philtrum and narrow lips.
He generally hides his eyes under a hat brim, but they're a muddy gold, as all his mother's people's are.
Treter is apprenticed to Summer and lives with her most of the time. Summer isn't Treter's mother. Treter's mother was young when she gave birth to him, and had trouble coping with a kid alone. He enjoys a much less strained relationship with her after he moves out.
Shaw is an artificial construct built by Summer especially for Treter, designed to fill the gaps in his half-wired brain. Shaw's presence does not enable Treter to interact with the Spirit (he will likely never be able to), but does help balance out the chemicals.
Treter is pronounced tray-tah (English accent) and Shaw is as it's written (English accent, again).
See also: Pierre