Dagur the Deranged

Dagur the Deranged is a villain in the How to Train Your Dragon TV Series, DreamWorks Dragons: Riders of Berk. He entered in Season 1, in Twinsanity, as the chief of the Berserkers. He is voiced by David Faustino.

Personality
The title of Dagur the Deranged is actually quite fitting, as he is seen as violent and extremely unstable. At times he performs erratic acts without thought or reason, other than to shed blood and kill. He is especially eager to kill dragons and sees them as nothing more than targets for his sadistic sense of pleasure.

Riders of Berk
Dagur first appears in Season 1 of the TV series, Episode 15: "Twinsanity".

The Hairy Hooligans tribe are expecting an annual visit from the chief of the Berserkers, Oswald the Agreeable. But then when the Berserker ships arrive at the island, it is shown that Oswald the Agreeable's son, Dagur 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 the Belch to consider the treaty signed.

Defenders of Berk
Dagur appears in the third episode, "The Night and the Fury."

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, stating that he was going to finish him and his dragon himself.

Trivia

 * He is said to have overthrown his father, and pursues a mission to bring the Berserkers back to their old ways.
 * It is speculated that he may have killed his father when he says, "Put down that axe, Dagur!" This speculation is also strongly supported by a comment he makes in The Night and The Fury in which he says that his father was eliminated.
 * 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.
 * It's interesting to note that Berk feels it necessary to have a peace treaty that's renewed yearly with the Berserkers and hide that they train dragons (which is a good thing as Dagur threatens to attack if he finds the "army of dragons" rumor to be true), while in Dragon Flower, Stoick is perfectly fine with openly flying Thornado to meet the Chief of the Shivering Shores by himself. This indicates that Berk knows who will honor a treaty and who can be trusted, and that the two concepts are not mutual.
 * Dagur means day in Norse.
 * His name is likely a pun on the short ranged melee weapon the dagger.
 * In "The Night and the Fury" he says he has a sister.
 * Dagur's name was thought to be "Dagus" prior to his appearance.