Vua Trời, in Mường Bua Klơi, is the King of Heaven who governs Mường Trời, the uppermost of the tiered Mường worlds. The living petition him for favourable weather and fortune, and in the mo funeral cycle the soul of the deceased is conducted upward to appear before him and to receive its place. He presides over the celestial order that mirrors the earthly hierarchy of lords, and stands opposite the lords of the water world below. Colonial and later ethnography records him as the supreme heavenly authority of Mường religion rather than as a narrative protagonist, and traditions differ on how sharply he is distinguished from the Vietnamese Ngọc Hoàng with whom he was later identified.