3 Idiots

Three bullies from Osamu and Yūma's school, who are collectively known as 3 Idiots. In the manga, their names are not given and are referred to as No.1, No.2, and No.3. In the anime, the credits gave them the surnames: Eida, Bitō, and Shiihara.

Trivia

 * No. 1 is "the leader" of the group and Ashihara wishes to have him survive while refining his perception of danger.
 * No. 2 is "the most irritating one", but Ashihara finds him the most mobile and doesn't hate him.
 * No. 3 is "the pudding head". His hobby is being bad. He usually studies, and his family seems to be quite rich.