Grimbeard the Ghastly

Grimbeard the Ghastly is a character in How to Be a Pirate, the sequel to the book How to Train Your Dragon. He was not only the world's greatest pirate, but Hiccup's great-great grandfather as well. Grimbeard buried his vast treasure somewhere on the Isle of Skullions before his death, and Hiccup has to solve a riddle to find it before Alvin the Treacherous does.