Haruki Nakayama is a 22-year-old graduate student sharing his university with bandmate Akihiko Kaji and Yayoi Uenoyama. Standing 178 cm tall, born July 13 with blood type O, he initially sports long light brown hair secured by a clip, later cutting it short after emotional turmoil. He maintains light stubble on his chin and favors casual attire: unbuttoned hoodies over layered shirts, trousers, and brown shoes. He is the bassist, founding member, and oldest of the band "Given," originally "The Seasons," assuming the band's nurturing, motherly role. Haruki mediates conflicts between younger members Ritsuka Uenoyama and Mafuyu Satou, manages band logistics, and promotes their activities via social media. Outwardly cheerful and supportive, he harbors deep insecurities about his musical skills compared to his bandmates, often masking true emotions like sadness or anger behind casual smiles. His personality blends kindness, empathy, and reliability with occasional shyness, especially when flattered or touched by Akihiko. Before Given, Haruki faced setbacks: expulsion from one band for dating member Aya, and founding another group that disbanded due to conflict. He plays a Japan-exclusive Fender Classic 70's Jazz Bass in Maple and drives a van with license plate 580 22-58. Outside music and studies, he works part-time as a café waiter. Haruki's arc centers on his evolving relationship with Akihiko. He develops longstanding unrequited feelings, intensifying when Akihiko moves in after being kicked out by ex-boyfriend Ugetsu Murata. Their cohabitation creates tension, culminating in a non-consensual sexual encounter initiated by Akihiko after he learns of Haruki's feelings. Following this incident and Akihiko's permanent separation from Ugetsu, their relationship gradually shifts toward mutual respect and affection. Akihiko later confesses his love, vowing self-improvement to become worthy of Haruki, leading them to become boyfriends. Within the band, Haruki supports Mafuyu's musical growth, encourages lyric writing by suggesting drawing from personal emotions like love—unaware of Mafuyu's trauma—and facilitates communication. He grants permission for Ritsuka and Mafuyu to date, reinforcing his role as the group's emotional anchor. His journey involves reconciling his insecurities with his value to the band, navigating complex romantic emotions, and maintaining stability during the band's rise.