Michael and the Calamity Dragon fought Kytos together. He might not need any help from the Calamity Dragon, but the ancient creature didn't want to leave Kytos alone. He told Michael that he was going to kill Kytos if he failed to regain his fated position as the Guardian of the Origin Universe.
Michael didn't like the way the Calamity Dragon spoke, but he accepted the condition. He would have to kill the Primal if they didn't return to their sacred duty either way. They were too dangerous if let loose.
