Kousaka Kyousuke♂

Protagonist of the game and Kirino's older brother. He is a fairly ordinary second-year high school student who wishes for nothing more than a peaceful life until he accidentally discovers his little sister Kirino's otaku hobbies. Even though Kirino is mean and disrespectful to him, he tries to be a good elder brother to her, giving her advice as best he can, and helping her to continue in her hobbies and make new friends. He is a responsible and reliable person who cares deeply about the welfare of his sister and of his friends.

[From AniDB]