Abyssbell, known as the Jashin Emperor and also called Jashin-kun, emerges as an enigmatic force within the narrative. He contacts Win Kirifuda immediately after Win encounters the "Boundary Line" – the mysterious divide separating the ordinary world from a devastated alternate reality. Abyssbell delivers a cryptic message to Win: "the duel to take everything back will begin soon," positioning himself as a herald of looming conflict tied to Win's lost memories and the ruined world beyond.

His presence manifests primarily from the shadows, especially within that destroyed world across the Boundary Line. Abyssbell displays intimate knowledge of supernatural phenomena and the human world alike, including familiarity with illicit networks like the dark web's "Demon Lord." This platform facilitates trade in illegal goods, murder orders, and otherworldly artifacts such as "talking cups" or "lost souls," suggesting his reach spans multiple realms.

Throughout the "Reaper of the Moonlight" events, Abyssbell continues communicating with Win from beyond the Boundary Line. While his motives remain deliberately obscured, he exhibits specific interest in actions like Ballom's widespread murders, seemingly enabled by a "contract" with an individual named Kyoshiro.

Abyssbell = Jashin Emperor is further linked to potent supernatural artifacts. The "Crystal Card," a powerful item entrusted to Win by Crysta, becomes a target traded on the dark web for an unprecedented 15 billion yen, underscoring its immense significance and hinting at his potential indirect influence over such coveted objects. His shadowy presence and cryptic guidance persistently intertwine with Win's quest to reclaim his past and confront the forces that shattered the alternate world.