Yamata no Orochi
There were once 8 planets in the Onam System. Many years ago, in the "time of the gods", there was a war against the evil monster Yamata no Orochi (an 8-headed dragon). The gods won the battle. Yamata no Orochi was locked into 8 capsules, one of which is buried deep in the center of each planet. Nobody was supposed to have access to the core of the planets. However Tsukuyomi, an evil "god" who rules Yomi, succeeded in reaching the capsules one after another. Seven of the planets were destroyed using his powerful robots, the Evil Sky Warriors. However, when he tried to acquire the last capsule from the planet Ismo, the most powerful Sky Warrior, Susanoo, got out of control and was blown away.