User blog comment:Dragonking99/Who is the most powerful dragon in the dragon world ?/@comment-6800048-20140325195908/@comment-3230751-20140326213933

I personally think Toothless attacked the Vikings because he was fully aware of the Red Death and he had just as much a part to play in that massive dragon's plan as any other. He may not have stollen food, but he took out artillary and allowed much more food to be taken. However, once he is crippled, he can no longer do that, and so when the Red Death sees him after probably weeks of absence, he tries to eat him as punishment for failing in his purpose. Anyway, I think it is clear that Toothless is fully aware of the Red Death and even under its sway at first... simply by the way he acts when he gets into the nest and the fact that he flew to the nest at all. So, yes, I think Toothless attacked the Vikings for the same reason as every other dragon: fear of the Red Death.