His name is Ryōmen

Sukuna weaves a spell that helps the angel get out of the water, he gently places her on one of the stones. The angel begins to cough water trying to get air into his lungs, Sukuna’s hoarse voice speaks “What do we have here? A cute angel is in trouble.” He looks at her with grace “Are you really an angel? Because if you say yes, believe me you are the stupidest angel I have seen in hundreds of years.”

It is said that when the gods were bored they created humans, angels and demons. Sukuna was a demon, their king, in charge of ordering chaos, on the other hand, the angels had the mission of bringing peace. Among the heavens of paradise a new angel was born, her body was that of a very beautiful young woman. One afternoon, Sukuna finds an injured angel drowning in a waterfall, out of pure curiosity he takes her out of the water and sees that she is an angel, he asks himself how stupid would an angel be to drown like that? The young woman begins to wake up and flaps her wings taking in air, looks at Sukuna and thanks him. Sukuna tells her “You are the stupidest angel I have ever seen, a real angel would never drown like that”

The angel that Sukuna meets is inexperienced, she doesn't know how to control her power and much less know the rules of the gods, she is totally pure and innocent since she was born recently, so at first they can't touch each other since the angel has a kind of spell that makes sparks fly and causes pain to both of them at the slightest touch, and she still doesn't know how to deactivate it. At first Sukuna is slightly rude to her, desperate for the angel's innocence, but as the days go by they venture into a series of conflicts where they begin to get to know each other, the angel comes down from heaven from time to time secretly to see him and learn more about him, as the days go by they both fall in love, but their love is forbidden by the difference in their natures, leading them to defy their creators, the gods.