Kotegawa Yū

Yui's 19 year-old brother, Yuu is a ladies' man, something Yui dislikes.

Personality
After finding Rito and Yui being chased by hoodlums, he defends the two from the ruffians, while commenting that he hopes Yui will grow to be more mature.[13] At the moment, he is dating Akiho Sairenji, Haruna Sairenji's older sister but unknown to him she isn't taking the relationship as seriously as he does.[14] He also is one of the few people to know that Rito is Riko.