About Regin
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 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.