Masato Rinno is a classmate of Doremi, Momoko and since Dokkan, of Hana. In 3rd and 4th grade, he was in the former class 1. He was the class representative of class 5-1 and 6-1. He also wanted to be the head boy, but lost against Tamaki Reika.
Masato is the son of a doctor. He is smart but also arrogant. He matured later in the series.
Masato has black short hair and a mushroom head. His eyes are grey. Masato is light-skinned.
He wears a blue shirt and brown shorts. He also wears white socks and blue shoes.