Tsutomu Tachibana is Makoto Okano's close friend, known for his clumsy nature. He persistently flirts with women, often leading to physical reprimands. His interactions with Kasumi Shikouin establish a recurring love-hate dynamic. Kasumi wears special glasses to suppress her ability to see others' true emotions and frequently buys tea leaves from Hikari's shop. Despite Tsutomu's constant advances towards various women, his relationship with Kasumi remains a consistent element, defined by conflict and tension.

At a summer festival, Tsutomu treats Kasumi's foot injury. Makoto and Hinata misinterpret the scene, assuming a compromising situation due to Tsutomu's reputation. Throughout the series, Tsutomu primarily serves as comic relief. His perverted tendencies and subsequent comedic punishments repeat without significant evolution or deeper exploration of his background. Substantial character development or expanded backstory is not depicted across the anime series, OVAs, or other official media.