Berk's Forumvine

Watch at 1 minute into Have Dragon Will Travel Part 2. Dagur says to Hiccup that it wouldn't be a family reunion without him. He already has Heather and Windshear in chains. So he is alluding to the fact that Heather is his family.

Hmm, I feel this may be stretching a specific line of dialogue to fit this particular idea. Don't get me wrong Dagur definitely could have know and there isn't really anything disproving the idea. With that said there's not really anything proving it either(at least nothing concrete). Personally I just don't think this is the thing that proves it.

All things said though, it could be proof Dagur knew all along. Or it could just be the writers being clever with foreshadowing what was to come.

I had accidentally read a spoiler about Heather being Dagur's sister before I first watched the episode, and from the point of view I had, it totally seemed like he knew. Like Demonwolf002 says, though, there's no real proof either way, but he certainly didn't appear surprised when Hiccup revealed the truth to Heather later in the episode...

Waiiit guys...



In the night and the fury Dagur mentoined that his sisters favorite weapon is a shield... in Race to the Edge Heather said she remembers the shield of her father...



Yep, Dagur definetly knows about Heather, doesn't he?