River Butterfly

River Butterfly (voiced by Alan Tudyk) is the former king of the Kingdom of Mewni, ruling alongside his wife Moon Butterfly, and Star Butterfly's father. Born into the Johansen clan of barbarians, River was crowned King of Mewni through his marriage to Queen Moon Butterfly.

After Eclipsa assumes the throne of Mewni, River now helps his wife in maintaining a society of Mewman refugees.