Regin

Reginn, often Anglicized as Regin, in Norse mythology, was the son of Hreiðmarr and foster father of Sigurd. His brothers are Fafnir and Ótr. When Loki mistakenly kills Ótr, Hreiðmarr demands to be repaid with the amount of gold it takes to fill Ótr's skin and cover the outside. Loki takes this gold from the dwarf Andvari, who curses it and especially the ring Andvaranaut. Fafnir kills his father for this gold, and Regin gets none of it and becomes smith to the king. He eventually becomes Sigurd's foster father, and teaches him many languages as well as sports, chess, and runes.