Black Knight Faust enforces the Machine Empire’s dominion as a high-ranking lieutenant under Queen Promethium and later Maetel, specializing in psychological warfare and direct combat against rebels like Tetsuro Hoshino. His connection to Tetsuro’s past emerges violently when he triggers a traumatic flashback of the protagonist’s mother’s death, exploiting this vulnerability to fracture Tetsuro’s resolve.

Faust governs the distribution of energy capsules—harvested from processed human remains—that power mechanized citizens. Marketed as essential for survival, these capsules imprison mechanoids in psychological dependency rather than biological need. He staunchly upholds the system, framing it as vital to imperial supremacy despite its reliance on mass human consumption.

A familial revelation during their final confrontation exposes Faust as Tetsuro’s father, transforming their battle into a clash of ideologies. Faust personifies the Machine Empire’s corruption, advocating mechanized immortality as liberation from mortal suffering while dismissing its dehumanizing toll. His warped idealism forces Tetsuro to confront the moral cost of eternal life.

The Ghost Train, Faust’s spectral warship, haunts resistance forces, transporting captured humans to processing facilities and cementing his role in imperial expansion. His reign collapses during a decisive battle aboard the Galaxy Express 999, where Tetsuro’s rejection of mechanized eternity and the empire’s unsustainable practices culminate in Faust’s destruction.

His legacy endures as a manifestation of humanity’s struggle against mechanization—a personal antagonist to Tetsuro and a symbol of the empire’s ethical decay.