The sentient that is responsible for the body-swapping phenomenon, he normally takes over the body of Gotou Ryuuzen. He is not limited to possessing only Gotou, as he was able to possess Cultural club members without difficulty.

He wishes to be entertained. He picks the Student Cultural Society club members of the Yamaboshi Private High School, just because he thought they are an interesting bunch.

He has control over the Body-swapping phenomenon, capable of taking over anybody he wishes. He can start and end the body-swapping process; however he allows the body-swapping to randomly choose the candidates amongst the group as it will be more interesting. He is also capable of letting the candidates choose who they wish to body-swap with among themselves, but only when he desires it.

(Source: Kokoro Connect Wikia)