#merciless

Jeep's weather report, gusts of wind with occasional clumps of leaves.

Merciless/The Green Death, learns of a prophecy that a human boy named Hiccup is going to kill him. So he sends Wodensfang after him to assassinate him, but that act is what leads to the Green Death's eventual death. The Wodensfang grows attached to Hiccup the First, teaches him about his language and dragons and delivers him the jewel, which Hiccup uses to make the Green Death stop the war and to live in exile.

That leads to the Green Death to eventually wake up some 600 to 700 odd years later on the beaches of Berk where Hiccup the Third kills him when he once again preys on other dragons and humans.

Grimbeard the Ghastly learns his third son will be Hiccup the Second and doesn't want a Hiccup ruining his kingdom like Hiccup the First supposedly ruined his father's kingdom, leading to the settlement of the Inner Isles.

So he leaves Hiccup the Second to die somewhere, which is what leads to Hiccup to be raised by dragons for the first seven years of his life only for Grimbeard to then come back for him when he thinks Hiccup surviving all this time means the Gods have spared him. That action directly leads to him having a son who is as much human as he is dragon and to Hiccup's biological brother, Thugheart, to turn against him and make up a lie that Hiccup means to kill Grimbeard in a dragon rebellion. Grimbeard killing Hiccup and finding out the truth breaks him and leads to the kingdom being split up anyway.

My personal headcanon design for Merciless from No mercy