In the second episode of the anime anthology, Kuwano is introduced as a deeply embittered man whose past connection to a teacher, Chieko Kawaguchi, drives him to a desperate and violent act. He was once a promising student who studied alongside Kawaguchi, possessing good grades and a clear path toward a prestigious college. However, his life took a drastic turn following a romantic rejection from her, an event he holds as the single source for all his subsequent misfortune. Unable to move past this perceived ruin of his future, he arrives at Kawaguchi's classroom armed with a gun, announcing his intent to exact revenge on her for derailing his life.

Kuwano's personality in the situation is a volatile mixture of menace and pathetic desperation. He is consumed by a fixation on Kawaguchi, and his demand for revenge quickly reveals itself as a twisted negotiation. When Kawaguchi offers to do anything he wants in exchange for the students' safety, he interprets this as a sexual proposition and agrees, exposing the selfish and predatory nature of his obsession. His actions hold an entire classroom hostage, creating a moment of high tension that is both threatening and tinged with the absurdity of his complete breakdown. In this context, he serves as the primary antagonist of the episode, a tangible obstacle born from past grievances that forces the protagonist, Sasaki, to confront his own beliefs.

Despite his role as a catalyst for conflict, Kuwano is given a brief moment of development that subverts the typical role of a gunman. He is not portrayed as a hardened criminal but as a broken man susceptible to manipulation. When the student Sasaki claims to be from the future and weaves an elaborate, hopeful story about Kuwano studying in prison, finding love, and having a family, the gunman is visibly moved. He falls to the floor crying, his resolve crumbling as he latches onto the possibility of a happier future. This intervention works, leading him to surrender and accept his fate, expressing a resolve to study hard while incarcerated. This turn reveals a core vulnerability beneath his angry exterior. Kuwano is not depicted as having any notable superhuman or special abilities; his power in the story comes solely from the threat of his firearm, making his emotional defeat by a student's words all the more significant.