Hokuto is a friend of Kousuke Shirai and Ataru Moroboshi from class 2-4 at Tomobiki High School. Although a friend of Ataru's, he and Kōsuke will not hesitate to bully and even backstab Ataru to get Lum's attention.
He doesn't appear in the first anime adaptation of Urusei Yatsura, where he was replaced by a character with similar sounding name who's basically a parody of Kenshiro from Hokuto no Ken.
(Source: Urusei Yatsura Wiki)