Mad Saulus leads Section B, a faction of bikers, criminals, and violent individuals dwelling within Evil Town's subterranean ruins. He commands through ruthless force, sanctioning their brutal survival tactics—including rape, murder, and extreme violence against weaker survivors. His second-in-command and romantic partner is Blue, a loyal hermaphrodite sadomasochist who never betrays him; their bond features mutual affection, driving Saulus to profound grief upon Blue's death.

Physically imposing yet smaller than Violence Jack, Saulus possesses distinct traits in the OVA adaptation: blindness in one eye, exposed flesh surrounding the injured socket, severe balding, and several missing teeth. His manga depiction diverges, bearing resemblance to Mad Max 2's Wez.

Saulus initially exploits women and resources alongside Section A after Evil Town's submersion. He perceives Violence Jack's emergence as a threat. When conflict erupts between Sections A and B, Jack defects upon discovering Section A's equal brutality. Section B triumphs over Section A, aided by Kawamori's betrayal—whom Saulus executes by stomping. Saulus then leads Section B against Section C, culminating in his personal battle with Jack. Jack overpowers him, hurling him through a stone wall (OVA) or strangling him unconscious (manga).

Following Section B's abuse of Section C's women, Jack retaliates, slaughtering Section B members and dismembering Blue. Saulus returns to find his followers slain and Blue's corpse. Consumed by anguish, he devours Blue's remains to merge their power. This act triggers a transformation into a demonic red monstrosity sporting a backhair ponytail (exclusive to the OVA; he remains human in the manga despite consuming Blue). In their final battle, Saulus seizes Jack's knife and stabs him in the chest. Jack ultimately prevails, impaling Saulus through the head with the blade. Mortally wounded and reverting to human form, Saulus experiences a final hallucination of Blue before dying.