Ri Haku manifests as a supernatural entity. He initiates the narrative by hosting a drinking contest, challenging participants while employing psychological tactics. He deliberately allows opponents to become intoxicated before using intimidation to secure wins. Later, he organizes a spicy food eating competition at a used book festival. Challengers endure extreme conditions: consuming a blazing hot pot filled with peppers while confined under a heated kotatsu, wearing warm clothing, and limited only to hot tea. Victory yields a rare book from his extensive collection. A childhood picture book belonging to another central character is present among his festival offerings, drawing multiple characters into his contest. His control over the books ends when a divine entity intervenes, redistributing them at reasonable prices with a protagonist's aid. Ri Haku indirectly causes a widespread illness after another character consumes his leftover alcohol, resulting in a cold affecting numerous city residents. His final act involves gifting the recovered picture book to one protagonist, facilitating a key connection. His parting words, "The night is short, walk on girl," serve as both encouragement and a thematic refrain. Ri Haku embodies elements of chance and fate within the story's exploration of interconnected lives.