Sasuke Mizunosaki is the elementary school-aged son of Sakura Mizunosaki, a neighbor of the main couple. He lives with his unmarried mother, who works as a nightclub hostess.

Characterized as a "Dirty Kid," Sasuke displays overtly perverted behavior despite his youth. He openly expresses lustful feelings toward the teenage protagonist Asami Onohara, causing her annoyance. His actions are obnoxious and disruptive, routinely sabotaging intimate moments between Asami and her husband.

Within the narrative, Sasuke functions primarily as a persistent cockblocker and comedic obstacle, preventing romantic developments between the central couple. His role remains static throughout the available media.