Wataru Sakurai is the central protagonist, possessing brown eyes and short brown hair, often depicted wearing glasses. Raised solely by his father after his mother's death shortly following his birth, he carries a lifelong absence of maternal warmth, manifesting as a particular fascination with large breasts.

Initially reserved and hesitant, especially around women, his personality develops through interactions with his childhood neighbors, the Fusono sisters Tomoka and Fumie. Upon his return, these sisters actively pursue him, helping him gradually overcome his shyness. Despite this growth, he remains notably indecisive in romantic contexts, struggling to commit to one partner and frequently finding himself in multi-partner dynamics. His relationships are defined by mutual consent and attraction, with the sisters' proactive approaches driving much of the narrative's intimate developments.