Don Horror is a monstrous six-armed idol-like being who is the leader of the criminal organization Makuu. This powerful villain wants to erase Earth, the obstacle that prevents his conquest of the universe, & is ready to use any means to destroy it. He lives in the Makuu Castle, which flies in the Makuu domain/tunnel. He is immobile throughout; how he gave birth to a son by Kiba is a mystery that remains unsolved.

Don Horror and the Makuu were eventually defeated by Gavan, resulting in their Makuu Space collapsing significantly. However, Ashrada, a descendant of Don Horror, conspired with Zangyack to use Gavan to catalyze the blood of Don Horror in his veins, which would make Makuu Space expand and consume the Earth. This plot was foiled by Gavan and the Gokaigers, who destroyed Ashrada.

He was almost resurrected by Brighton, only to be stopped by the new Gavan.