User blog comment:Dragonmentor123/Is there a reason that Toothless might be the only night Fury?/@comment-4122072-20140825062415/@comment-7628730-20140826215907

Oh, ok. How about this then... Hiccup and Astrid have kid(s), Fishlegs marries Heather, (they seem like they would get along really well), Ruffnut marries Eret or Snotlout, and they all go on one big adventure to find more Night Furies and fail. Then they all come home and decide that its probably for the better. Then, BAM, a giant asteroid crashes into berk and kills all of the dragons. The end, and there's your explanation about the dragon extinction.