Relationship between Edward and Seth

-- This may be spoilerish if you haven't read the fourth book! --

In Breaking Dawn, Seth is shown to have developed an unlikely friendship with Edward, and attends his and Bella's wedding. Seth remains a constant presence throughout the final book in the series. He is initially the only werewolf to feel completely comfortable being around the Cullen family. He also has, according to Edward, very honest and pure thoughts, something that endears him to the Cullens, and Edward in particular.

- from Wikipedia.org