Endeavour or Endeavor (in the US) is the sword of Hiccup Horrendous Haddock III, which he acquired in How to Be a Pirate and uses in every book thereafter. Hiccup uses Endeavour in all the subsequent books, and it has allowed him to successfully defend himself from Alvin the Treacherous, Norbert the Nutjob, and even the Hairy Scary Librarian. Hiccup always keeps it with him in case he is attacked by Driller-Dragons. Like Hiccup himself, the sword is small and unimpressive at first sight, but very reliable in a tough situation.