The Xarai are cannabalistic zombie-like creatures that were formerly Peacekeepers on board a Leviathan prison transport for the criminally insane. The Sebaceans slowly devolved into the Xarai as a result of twinning technology used on them by the sole inmate on the ship, Kaarvok. The twinning or cloning technology Kaarvok created takes one person and creates an exact duplicate to where there are now two persons, "both equal and original."
The zombie-like state in which these now mindless former Peacekeepers is a direct side effect of being twinned too many times. Kaarvok considers the Xarai to be his family, as well as his main source of food.
- (3.06 "Eat Me")