The Ultima Gem (God Lands Era)

Normally situated on the chest of Dragora Galaxia, the Ultima Gem serves as Dragora's "heart", so to speak. In an extremely rare chance, however, immediate fatal blows to Dragora are dealt when the Ultima Gem is struck with enough damage to it... But that extremely rare chance isn't referring to Dragora's demise, but rather what becomes of the now rendered unstable Ultima Gem. In the case where the Ultima Gem is at least partially intact when a Dragora is killed, the Ultima Gem briefly gains it's own savage mind and delivers complete and utter chaos upon a target, transforming into various different forms during it's rampant state, and stays this way until the Ultima Gem is either stabilized by repairing it and thus reviving Dragora, or by shattering the Ultima Gem like glass, but such a task is not easy due to the anti-matter particles surrounding it at all times.

Origins:
The Ultima Gem first appeared in Ultimorian History as an Artifact of Doom more or less, since it's discovery foretold the arrival of a new god who would lay waste to the world and shatter it into glass-like fragments. Dragora was the very first user of the Ultima Gem, a history which would remain in Dragora's bloodline to this day, and Dragora's own physical form was heavily distorted and mutated into his current look due to the sheer powers of the Ultima Gem conflicting with his normal powers. When Dragora claimed the gem for himself, he did exactly as the prophecy depicted and Ultimoria was destroyed in many fragments which would later reform into trillions of other universes as a result, with the central piece remaining where it was and reforming into a new Ultimoria.

During the God Lands Era, Grandis secretly modified a bit of the Ultima Gem's history as an Easter Egg to give it abilities directly lifted from Master Core from Super Smash Bros., and as a result there now exists a very scarce chance that when Dragora is slain, the Ultima Gem he has remains intact to destroy Dragora's remaining body and reform itself into a Omnishifter with sheer uncontrollable power that output much more power than any other Ultimorian has been known to do, and is capable of absolutely insane attacks that even Chronicle King would be weirded out by this artifact's sheer reality warping abilities. The Ultima Gem effectively destroys everything about the Laws of Physics in this state of instability, and until it is either shattered like glass or repaired, it will remain an unstable gemstone with a floating mass of Anti-Matter surrounding it as it takes on the forms of various entities with this substance.

The exact reasons as to WHY Grandis made this possible is never clear, since Martin outright HATES fighting Master Core and wouldn't want to deal with anything like it on his own. Perhaps given the fact Grandis and Martin are both amplified in power and capabilities that it didn't matter to them, and that they both were powerful enough to handle the Ultima Gem's attack methods should the occurrence ever happen? It makes you wonder just how far insane Martin had become ever since becoming an undead Werewolf, and some of these ideas of insanity had led to other retcons no different from how the Ultima Gem can now potentially function.