Andvari is a dwarf who appears in the Magnus Chase series. He is very old and skilled with magic. He has a large amount of treasure with him and a magic ring which controls that treasure. Andvari stays in Alfheim, in a lake, as a fish.
Magnus Chase and Hearthstone set out to find him to steal his treasure. After Hearth lifts a river and Magnus reads all the fish's minds and finds the dwarf. He changes back into his original form and, after interrogation, gives them his treasure and ring. He warns them of the curse placed on his treasure before they leave with his treasure.