when godzilla was awakened to battle the xilien army of monsters, the controller was unfamiliar with the beast, and sent the monsters to defeat him. one by one, gigan, zilla, kumonga, and kamacuras all fell, and even a team attack by rodan, anguirus, and king caesar failed to stop godzilla. upon landing in tokyo, godzilla simultaneously obliterated ebirah and hedorah (hedorah's location prior to this scene is a mystery, as he is not seen at any other time in the film, leading to the belief that he was in the wrong place at the wrong time; however, hedorah could have merely been making a cameo appearance). enraged, the controller sent a secret, last monster, monster x, into battle via an enormous asteroid in which he was contained. the monster was much more powerful than the previous monsters and overpowered godzilla numerous times. when mothra (whom the controller was also unfamiliar with) arrived in tokyo, a repaired and upgraded gigan was sent to destroy her. monster x and gigan briefly double-teamed against godzilla before gigan was destroyed by a kamikaze attack from mothra. as the two monsters fought, the controller revealed to the heroes that mutants were the product of interbreeding between humans and xiliens in the past. he also revealed that he was a kaiser (spelled as "keizer" for unknown reasons)- an extremely rare type of mutant who is granted superpowers due to the fusion of m-base and human dna. kaisers are able to control any other lifeform by telepathic means if that organism has m-base. ozaki, one of the mutant soldiers, was also a kaiser, and defeated the controller in battle. moments before the xilien mother ship came crashing down around him, the controller is seen screaming in anger and agony among the explosions, due to his defeat. the scene shifts back to monster x and godzilla, who continue to rage in their war for ultimate defeat of the other. after they are both blown away by a massive conflagration when their energy beams collide, monster x transforms into a hideous monstrosity known as keizer ghidorah.