Sachio Sasame

Possesses type synthetic power equivalent to level 5 and is able to use it to make hypno, to create visual information. He is 11 years old and was introduced after the timeskip in the omake pages.. Previously part of a team with his twin sister, he apparently has a large sister-complex and is very besotted with Yukino to the point of not wanting her to grow up and wanting to protect her for his entire life. Has a dark personality. When he first appeared, he was posing as his sister using his synthetic esper powers, planning on breaking the team up with internal strife. He is able to use his powers in a number of ways, such as changing into Yukino, transforming Yukino into something else, changing Yukino's grades, etc... all of them seem to be limited only to Yukino in some manner, however. On his proper appearance in the manga, he has learnt to show illusions of other people. (Source: Wikipedia)