Birthday: June 10
In 5th grade in Part One, enters Seishuu High School at the start of Part Two. Kou lives down the street from the Tsukishima family and is treated like one of the family when he visits their house, batting cage, or coffee shop. He has been practically inseparable from Wakaba since their birth on the same day in the same hospital. While he shows little interest in baseball to outsiders, he has practiced daily at the Tsukishima Batting Center since he was old enough to swing a bat, enough so he is an excellent batter, especially against fastballs.