『Rinko Kuzaki』

Rinko is Yuto's tomboyish childhood friend and next-door neighbor. She had a very close friendship with Yuto, as she helped him out of his depression when he first moved to Takamiya and cried along with him when his parents died. She also has feelings for Yuto until Himari and the other girls appeared, causing her to display a tsundere personality as a result of their constant flirting. She also suffers from an inferiority complex from their well-endowed breasts(sans Shizuku). She is also a remarkable athlete, excelling at nearly every sport at her school.

Rinko always tends to ruin every romantic or perverted moment Yuto has with another girl by hitting him with her signature nail bat(or any other object she could find) despite the fact that he had nothing to do with it in the first place. However, despite all of this, she still wants to support Yuto to the very end even if he does become a full-fledged Demon Slayer, believing that she is the only person good for him due to their long relationship and that all he ever wanted was a normal life. Rinko is always seen wearing two red ribbons in her hair; a tradition involving them is that, every year during a summer festival, Yuto would buy her a new pair for her to wear year round and she would tie last year's ribbons to a treebranch. She owns a pet cat named Ranmaru(蘭丸).