須藤 孝道

The student council president and Keita's childhood friend. He is Mio's elder brother, and he's fond of her. He is jealous of Keita who has three little sisters. Mio acts harshly towards him.

He said something perverted like "I want love from my little sister" with a serious face. Feeling creepy, all of the student council officers resign from the student council. Therefore, Keita comes to help when it  is busy. They make an organization called "Little Sister Union" and discuss everyday how to be liked by little sisters.