Syzygy

https://www.deviantart.com/daitenmasterlist/art/Daiten-1231-935480786

The Syzygy is a pair of Daitens who, when Heaven collapsed, chose to fuse their souls into one body in order to survive. They lead a religious sect on a new world; their power was already akin to a god's, but with the devotion of many magical practitioners, it has only grown. They spend much of their time in meditation, watching over the world they have landed on and trying to seek the family they lost in the Fall.

They were once two people: Ansell and Caliban. Ansell ruled the domain of Light, bright and blinding; she was perceptive and honest to a fault, and never tolerated even the tiniest white lie. Her counterpart was Caliban, who was quiet; it would watch the people around it for a long time before ever speaking with them, but it always seemed to know them straight to the heart. There were no secrets from either one of them; they each had their ways of pulling truths from people, willing or not. It was common knowledge among their family that if you wanted to know something, Ansell and Caliban would have the answers. Getting them to share those answers was another story.

The Fall of Heaven destroyed everything. Separated from their home and their family, far from anything familiar, Caliban and Ansell were lucky to have each other. Rather than risk losing each other, they made the drastic decision to never be separated again: they left their bodies behind and fused their souls, becoming the Syzygy. This also fused their magics; where once they ruled Light and Dark separately, now they rule them together, and with greater control than ever before. Their power drew followers, and over long decades on their new world they built a new home: a temple to the sun and moon, where they sit in meditation and watch over their followers.