Astrid Hofferson is a young Viking girl of the Hairy Hooligans tribe who attends Dragon Training with Hiccup and the other Viking teens. She is striking, tough, beautiful and her determined and strong persona makes her hard to impress. Astrid is Hiccup's main love interest in the film. In spite of initially not liking Hiccup or his new found friendship with Toothless, she soon has her opinion changed and helps to try and keep Toothless a secret.
Astrid does not appear in any of the books in the original series and is an original character designed for the film. It is possible she is based on the character Camicazi from the books.