Sköll

Sköll is the son of Fenrir, and grandson of the giant Angrboða and God Loki. He was originally killed by Rias Gremory and Sona Sitri's Peerages, but as of volume 7 of Highschool DxD: Jester of the Gremory Clan, Sköll was reincarnated as Maho Gremory's third pawn, and as Uther Pendragon's Familiar.