The Murderous tribe sacrifices people to these dragons. It all started with Madguts Ancestor Murderous the Magnificent who won the first intertribal swimming race against Grimbeard he Ghastly and become king of the archipelago (With the tribe believing that Grimbeard died in the waves). starting the tradition of sacrificing people to the Sky Dragons. However, after three months, five days and six hours later Grimbeard becoming the winner of said race and demanded that Murderous be sacrificed to said dragons. The Murderous tribe kept the tradition in honor of the man with his descendant waiting for a chance of vengeance.