Her name is Phio, in her clan's language it means Phoenix. The Phoenix is their symbol of hope and prosperity since the phoenix gives rebirth, and thus children named after a phoenix is blessed with luck and reincarnation once they die.
Phio is Jeremy's best friend and has been tormented by him all her life, since both of them are sort of immortal (Jeremy is but Phio is not - she may be long lived but at some point she will have to die) so she's dealt with him since leaving her home