Sea Prince and the Fire Child

Fuente: AniList

The God of Water and the Goddess of Fire, who once lived in harmony, were torn apart by the Lord of the Winds. Their children, Sirius, heir to the Water Kingdom, and Malta, heir to the Fire Kingdom, become aware of the existence of their other worlds and fall in love. Their parents, however, disapprove, leading to a tale of star-crossed lovers trapped between life and death, water and fire.