"I will avenge you, father. I will save you, mother. I will kill you, Fjolnir."

These are the only tasks on Alexander Skarsgård's mind as the True Blood and Big Little Lies star transforms into a vengeance-seeking Viking in the first trailer for The Northman.

Robert Eggers, who directed smaller, more confined indie films The Witch and The Lighthouse, tells EW over a call from London, where he's editing the movie, that this epic saga is "by far the hardest thing I've ever done and by far the most ambitious."