Thenn warg

AThenn warg is a character in the fourth season, debuting in the season premiere. He is played by Joseph Gatt.

Background
He is a member of the Thenn, a tribe of Free Folk known for their practices of ritual self-scarification and cannibalism. He's also a warg, capable of entering the minds of animals to see through their eyes and control their actions. He's bound to an owl, allowing to act as a scout for Styr, the Magnar of Thenn.

In the books
In the A Song of Ice and Fire novels, even though there are several wargs in Mance Rayder's army (Orell, Varamyr Sixskins, Borroq), there's no mention of a Thenn warg