'Vikings' Season 4 Latest Spoilers, News & Update: Ivar The Boneless Takes On His Revenge For Ragnar's Death; Aslaug's Sons Plan Their Revenge

Ragnar (Travis Fimmel) is dead and his sons with Aslaug (Alyssa Sutherland) are taking on their revenge towards Lagertha (Katheryn Winnick) in "Vikings" Season 4 Episode 16.