- Alex Høgh Andersen (Ivar Lothbrok / Ivar the Boneless)
- Jordan Patrick Smith (Ubbe Lothbrok)
- Marco Ilsø (Hvitserk Lothbrok)
- Peter Franzén (King Harald Finehair)
- Georgia Hirst (Torvi)
- Danila Kozlovsky (Prince Oleg of Novgorod)
Vikings — S4E1
Episode: A Good Treason
Air Date: 2016-02-18
Runtime: 47 min
Overview
A dangerously ill Ragnar returns to Kattegat, where his suspected death kicks off a scramble to succeed him. Meanwhile, Lagertha engages in a power struggle with her calculating, former second in command, Kalf. Rollo betrays his heritage and remains in Frankia. Floki pays the price for his brutality against the Christian priest.