Goro Mori is a fourteen-year-old student and a member of Hidomi Hibajiri's class, where he is close friends with Ko Ide and Marco Nogata. He is a slightly overweight boy with messy, buttercream-blond hair parted at the center, thin blond eyebrows, and brown eyes visible behind his white glasses. His clothing is notably eccentric, consisting of bright, often clashing colors and questionable accessories. He proudly wears a short skirt as part of his school uniform, adhering to a personal belief in a unisex fashion trend, a choice that defines his visual identity and sets him apart from his peers.

Initially serving as a source of comedic relief, Goro has an outlandish and wacky personality. He is stubborn in his beliefs and refuses to change his unconventional style despite the disapproval of his friend Ko Ide. Underneath his humorous exterior, however, he is a deeply insecure individual who desperately seeks companionship. This lack of confidence is most clearly demonstrated through his romantic life. He lies to his friends about having a girlfriend and, to maintain this facade, hires a girl named Aiko to pretend to be his partner. He is very jealous of Ko Ide's perceived success with women and expresses frustration when he feels overshadowed by his friend, at one point crying and shouting his frustrations into the ocean during a beach outing.

Goro's primary motivation revolves around his desire for affection and his efforts to convince others of his desirability. His central relationship is with Aiko, whom he pays to act as his girlfriend. While she maintains a shy demeanor in front of his friends, she reveals a crass and superior attitude when they are alone, showing a lack of genuine initial interest. Despite the transactional and precarious nature of their arrangement, Goro's actions later in the story reveal a chivalrous and determined side. His resolve becomes vital when he takes on the role of a guard for Aiko, who is revealed to be an important figure, and even serves as a bike chauffeur for her during critical moments. Through these actions, he ends his journey having evolved beyond mere comic relief into a truly helpful friend, and Aiko eventually develops genuine feelings for him in return.

His friendship with Ko Ide is complicated by jealousy, as Ide does not approve of Goro's fashion and appears to have more romantic success. In contrast, his other friend, Marco Nogata, is more accepting of Goro's quirks and serves as a passive but sympathetic listener when Goro feels overwhelmed. Goro does not demonstrate any supernatural abilities or N.O. channel capacity, instead functioning as a grounded, albeit eccentric, human character whose contributions to the story are emotional and logistical rather than combative. His development sees him transition from a pathetic and boastful liar to a more courageous and reliable individual who is willing to take action to protect someone he cares about.