Oji Hoshino

Oji Hoshino is a third year high schooler who is an observer in the program. He was born November 1st, is 165 centimetres tall, weighs 113lbs and debuted in episode 2 of the anime. He has yandere-like traits, forming a strong connection to one of the main characters, Yuuri Amagake.

(Source: Battle in 5 Seconds After Meeting Wiki)