Kim Jae is a submissive man the same age as Yul-seo. He works in the corporate marketing office of Oh Ha-jun’s father and attends the same elite university as Sangwoo (though his family pays for his tuition). He finds peace in being "tied down" and hurt by Yul-seo, but he never wants to hurt her in return. He is easily stimulated and deeply appreciative of her body. After their sessions, he often just wants to hold her naked in his city-center apartment, providing Yul-seo with a rare, quiet comfort. He is a regular at the café and a fan of the coffee there.