Genbu, one of the four Kitoralsus Agents, starts as an antagonist. He first assumes his Giant Monstrous Being form driven by curiosity about his enemies, openly challenging the Shinkalions and their pilots to test their strength. In this form, he consistently overpowers them until the N700A unit shifts the battle against him.

Later, Sougyoku forcibly transforms Genbu into his monstrous state. While powerful enough to overwhelm opponents, Genbu internally resists Sougyoku's control to minimize harm. This internal struggle allows the Shinkalion E5 to deliver a point-blank Gran Cross attack, neutralizing the threat.

Three years later, during Astrea's infiltration of the Omiya Branch amid the SUEI's conflict with the Teoti, Genbu willingly re-assumes his monstrous form. He uses this transformation to stall threats, buying time for personnel to deploy the Z units. During this engagement, he sustains a significant arm injury as part of a tactical bluff.

In the final phase of the plan to defeat Arabaki, Genbu transforms into his Giant Monstrous Being form once more. He coordinates with the Z units and the momentarily clear-minded Monsterized Teoti Warriors. Together, they destroy Arabaki's roots, marking a decisive alliance between Genbu, the Teoti Warriors, and humanity against a common threat.

Genbu evolves from an adversarial tester of strength to a reluctant combatant under coercion, and ultimately to a strategic ally who sacrifices his well-being for larger objectives. His actions demonstrate significant combat capabilities in his monstrous state, while his role shifts from challenger to protector as he aligns with former enemies against existential threats.