Kongō-sensei is the head of the Gems, acting as the teacher, protector, and father figure. He teaches the Gems about the current world and its history and decides the role suited for each of them. He has overwhelming offensive power and can disperse the Lunarians in one blow. He becomes incredibly intimidating when angered. Every time the Lunarians appear, one Gem from a pair of the patrol will ring their school's bell. He and the Gems will go to the scene and disperse the Lunarians.