Rekka and the Crimson Lotus uncover the Black Steel's sinister plot to create a superhuman race by fusing humans with demons, a process that releases defective monsters into the world. Driven by a desire for justice and Haruka's need for vengeance against the leader Yasha, the team launches a decisive attack. The battle culminates in the destruction of the Black Steel, ending their cruel experiments and avenging the lives they destroyed.