Who is Moksoon from Crystal Singer and what is their importance?

Moksoon is a crystal singer. He accompanies Killashandra to the ranges for the first time, after being assigned as her shepherd. Moksoon's memory, however, is so bad that he forgets who Killashandra is from minute to minute and tries to kill her several times. Killashandra decides to leave Moksoon a day early in order to protect herself from his memory lapses.