In Norse Mythology
Reginn, often Anglicized as Regin or Regan, in Norse mythology, is a son of Hreiðmarr and foster father of Sigurd. His brothers are Fafnir and Otr. 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, but eventually becomes a greedy dragon. Reginn gets none of the gold, but he becomes smith to the king and foster father to Sigurd, teaching him many languages as well as sports, chess, and runes.
In God of War (2018)
Reginn was captured by the Dwarf King and forced to act as Sentry of Konunsgard.