The character Fuyubachi appears in the eighth episode of Paranoia Agent as an elderly man who enters into a suicide pact with two other individuals he meets online, a younger man known as Zebra and a young girl named Kamome. Physically, Fuyubachi is depicted as old and frail, with white hair. He carries a bag of Chitose candy and relies on medication for an unspecified condition; when he fails to take his pill, he suffers from vertigo and momentary delusions.

Personality-wise, Fuyubachi initially presents himself as pragmatic and somewhat world-weary, approaching the planned suicide with a sense of solemnity. However, his behavior throughout the episode reveals a more complex and even playful side, as the group's repeated failed attempts at dying take on the tone of a slapstick farce. He expresses a clear moral compass when he is shocked to discover that Kamome is a young girl, believing it is wrong for a child to be involved in their plan. This leads him to suggest that he and Zebra should run away from her, convinced they are acting for her own good. Despite this, he cannot bring himself to abandon her, particularly after hearing her cry out that she does not want to be left alone.

Fuyubachi's primary motivation is to end his own life, but the exact reasons for his despair are only hinted at. He suffers from a disease that appears to be terminal or debilitating, which likely contributes to his desire for death. Some interpretations suggest he carries the Chitose candy, a symbol of longevity given to children at festivals, as a representation of happier times or a lost connection to a child named Sayo, whom he murmurs about in his sleep.

In the story, Fuyubachi acts as a reluctant leader for the trio, often suggesting their next method of suicide and attempting to maintain a sense of control over their situation. His role is also to provide a contrast between the weariness of old age and the eagerness of youth, as he is less enthusiastic than Kamome but more resigned than Zebra. A key relationship forms between him, Zebra, and Kamome, as their shared goal of dying transforms into an unusual, makeshift family bond. They care for one another, even as they try to leave each other behind for what they believe are noble reasons.

Fuyubachi undergoes a notable development by the end of the episode. After a series of comedic failures, he is the one who notices the central, haunting truth of their existence: none of them cast shadows, a detail that is confirmed when a living man walks between them without seeing them. This realization implies that their first successful suicide attempt had already occurred, and they have been ghosts throughout the episode, unaware that they are already dead. Upon recognizing this, Fuyubachi accepts their state and suggests they take a bullet train far away, leading the others away as they skip and sing.

Fuyubachi does not possess any supernatural abilities in the conventional sense. However, his most notable ability is his perception. He is observant enough to notice the lack of shadows, allowing him to understand the truth of their condition. Furthermore, the trio collectively possesses the strange ability to repel Lil Slugger, the series' antagonist, who flees in terror upon encountering them, suggesting that their status as spirits places them outside of his power or purpose.