No-one knows fully how this happened know it must be something to do with Milly's curse Brain Shadow which turns her into an evil and murderous person when fully exposed to the curse.
The Nameless Soul has had many encounters and fights during the time it has lived, one being a fight between The Universe Beast a beast with strength that seems to be infinite. The universe beast is the protector of the universe, but not the sole creator.
The nameless soul has an appearance of a mysterious being but can be soon identified due to the fact that it wears a white surgery mask and has long elven ears.
It is easy to know if the Nameless Soul is nearby as The Universe Beast appears with a world-swallowing rage which could easily destroy worlds beyond its own dimension if needed.
The universe beast always appears where The Nameless Soul will appear as it is a potential threat to the universe.
Dimension Travel - Unfortunately, being a Mu'ka it can travel to dimensions The Universe Beast cannot, causing problems in other dimensions. because it is difficult to know which dimension it travelled to, it waits until a weak tremor coming from the Nameless Soul's dark energy can be felt, which happens when the Nameless Soul is about to deliver the final strike to a being who tried to fight off it.
It has mastered its Dimension Travel at such precison that it does not fall unconscious after teleporting.
Brain shadow claws - Being fully exposed to the curse means that it can infect other with the curse, when The Nameless Soul turns back into Milly it is only a quarter exposed to the curse, making her self controllable again.
Only one one being came to be the successor and her name was MoonShadow.
MoonShadow is daughter of Milly and the only offspring that was given the BrainShadow curse through genetics. She quickly had the same symptoms Milly had got at the young age of 10,000.
Unfortunately, MoonShadow never became unexposed to curse making her bond with her dark side unremoveable. This made her permanantly the successor, Reincarnation.
Due to this The Universe Beast saw her as a threat and thus, the whole cycle began again.