They were an androgynous humanoid creature with no real physical form that hailed from The Light Realm.
Sometime after entering our Bubbleverse, they decided to sacrifice themselves to bring the Multiverse into existence. Holding a tournament to decide the God of this new Multiverse, they created beings capable of inheriting their power and ascent to become their successor.
As a final act before their sacrifice, they were also the creator of The One Rule.
Their preferred form bore some resemblance to White Chara.