Dagur the Deranged

Dagur the Deranged is a villian in DreamWorks Dragons. He first appears in Season 1 of the TV series, Episode 15:"Twinsanity", as the chief of the Berserkers. He is voiced by David Faustino.

Riders of Berk
The Hairy Hooligan tribe are expecting an annual visit from the chief of the Berserkers, Oswald the Agreeble. But then, when the Berserker ships arrive at the island, it is shown that Dagur, Oswald the Agreeable's son, has become the new chief of the Berserkers, and is now given the new title — Dagur the Deranged.

He came to Berk to renew the peace treaty between the Berserkers and the Hooligans. He spent most of the time insulting his father, and looking for dragons to kill. Later in the episode, when Barf and Belch bursts into the Great Hall, he led the Berserkers in catching them. Barf and Belch were brought to the arena so that Dagur and Stoick could kill them. Dagur was stopped by an "attack" staged by the other dragons, directed by their riders via hand signals. Dagur was forced to flee, but told Gobber to consider the treaty signed.

Defenders of Berk
The Dragon Riders were on Dragon Island on a training exercise to sharpen their stealth skills. Unfortunately, Dagur was also on the island with the goal of killing any dragon he encountered, and especially the Night Fury. Due to a twist of fate, he and Hiccup 'join forces' and Dagur even referred to Hiccup as his 'brother.'

Though the Dragon Riders tried their best to hide their dragons and the fact that Berk actually trains them, Hiccup was forced to reveal the secret in order to save Toothless. This enrages Dagur, who sees this as a violation of the peace treaty. However, despite his advantage of strength and rage, Dagur is defeated by Hiccup's tactics, shield, and Toothless' plasma flames. He later swears revenge, but orders his men not to touch Hiccup and his dragon, stating that he was going to finish them himself.

Trivia

 * He looks superficially like the Norse god Loki.
 * He is said to have overthrown his father, and pursues a misson to bring the Berserkers back to their orginal island.
 * Dagur will play an important role after being introduced in season 1.
 * It is speculated that he killed his father when he says, "Put down the axe, Dagur!"
 * In "The Night and the Fury" he says he has a sister.
 * His name means "day" in Norse.
 * Given how many details he knows of Hiccup's dragon-training practices and his victory over the Red Death — and particularly his unwillingness to divulge his 'sources of information' — it's speculated that Dagur is also secretly allied with Alvin and the Outcasts.