Arai was bred as an F-line labor slave designed for extremely heavy labor. He was freed when a Beowulf System-Defense Force ship captured the slaver he was aboard, and lived on the planet Berstuk in the Aldib System for some time before moving to Beowulf at the age of eleven and eventually gaining citizenship. When he was young, he was a thug, but then he met Audubon Ballroom leader Jeremy X, who "straightened him out". As an adult, he joined the Biological Survey Corps.