Murderous the Magnificent is the former Chief of the Murderous Tribe.
As mentioned in How to Ride a Dragon's Storm, Murderous the Magnificent challenged the then Hooligan Chief, Grimbeard the Ghastly to a swimming race. The winner would get their wish fulfilled. At first, it seemed that Murderous won, as he returned three days later. But then after three months, five days, and six hours after the starting day, Grimbeard returned bearing a strong physical appearance akin to that of a monster due to the fact that he was in the ocean for over three months. At first, Murderous and his men didn't recognize Grimbeard, but then saw the Stormblade sheathed on the man's belt, and Grimbeard spoke telling them who he was. Grimbeard then became the new victor of the swimming race.
The Friendly Intertribal Swimming Race became a tradition in the Barbaric Archipelago.
Murderous' also death had caused his descendants and successors to become embittered toward the Hooligans. The Murderous Tribe sought revenge, and came close to achieving it when Murderous' descendant, Madguts the Murderous cheated at the Friendly Intertribal Swimming Race that took place in How to Ride a Dragon's Storm, and had his competitors, Stoick the Vast and Big-Boobied Bertha prepared to be sacrificed to the Sky Dragons. This almost happened until Hiccup Horrendous Haddock III, Fishlegs No-Name, and Camicazi returned to Murderous Island and beat Grimbeard's record.