Berserker Tribe

The Berserker Tribe was a tribe of fierce Vikings led by Dagur the Deranged who served as the main antagonists of Dragons: Defenders of Berk and season 1 of Race to the Edge. They were one of the biggest tribes in the Barbaric Archipelago, who formerly were allies with Berk, before attempting to conquer them after realizing they had lied to them about dragons.

Origins
Berserkers were actual Norse warriors who fought in a nearly uncontrollable, trance-like fury. Most historians believe that berserkers worked themselves into a rage before battle, but some think that they might have consumed drugged foods.

Abilities
The Berserkers commanded a vast armada of ships. According to the stories told by Stoick's grandfather, the Berserkers had the ability to command the power of the Skrill, using tethered harnesses to force the dragon to attack with lightning.

Trivia

 * The Berserker's crest is a Skrill.