This claim-stone, affectionately dubbed Namey Rock by the twins, stated that the Dragon's Edge belonged to their family, as they are related to Magmar Thorston who dedicated the island to the Thorston clan.
In "Reign of Fireworms", Tuffnut and Ruffnut found it on Dragon's Edge. When they showed it to Hiccup, Astrid, Fishlegs and Snotlout, the others first thought that the twins might have made a fake claim-stone, but Gobber determined that it was real. It was created by the Twins' long lost great uncle, Magmar Thorston. This caused the twins to rule the island horribly, until they were forced to share the island in order to save it from the Fireworms who were burning the island to the ground. Afterwards, Meatlug ate the claim-stone.
|“||I, Magmar Thorston, hereby claim this island in my name and the name of all my family present and future, forever and ever and ever.||”|
|— Magmar Thorston|