Vikings season 6 spoilers: Ivar the Boneless' plan revealed in huge Oleg betrayal?

The promo for episode four was recently released, and shows off a brutal confrontation between Ivar and Oleg.

Oleg can be seen pushing his finger into Ivar’s chest, and growling furiously at him.

He said: “You can be very useful to me. But don’t ever betray me!”

While it looks like the pair will continue to work together for the time being, viewers should not be surprised if Ivar does double cross Oleg.