Keto serves directly under Buros within the Dark Joker organization. As a subordinate, he executes the group's objectives: contaminating Earth and Queen Earth with the Black Vaccine to eradicate life. His missions involve attacking protagonists like Ririka Moriya (Nurse Angel), Kanon, and their allies, often deploying Black Vaccine monsters through various schemes.

A fierce rivalry defines Keto's relationship with fellow high-ranking member Dewey. They constantly compete for Buros's favor, leading to intense infighting and discord within Dark Joker. This antagonism frequently escalates into direct confrontations, weakening the organization's internal cohesion.

During one coordinated operation, Keto and Dewey launch a simultaneous assault on Ririka and Kanon. Keto commands an electricity-based monster while Dewey controls a water-based one. The attack backfires when the water monster inadvertently contacts the electricity monster, causing their mutual destruction. This incident highlights Keto's tactical role and occasional coordination with other agents.

Keto participates directly in the physical assault against Kanon, contributing to the injuries that result in Kanon's temporary incapacitation. This action reinforces Keto's commitment to Dark Joker's destructive goals and his involvement in critical conflicts.

After Nurse Angel defeats Buros, Keto's ultimate fate remains unaddressed. His narrative concludes without details on his survival, capture, or any continued role.