Hiccup let go of Toothless.

It was just like that moment in the movie, when Hiccup let Toothless go so he could start his own family with me—the Light Fury. Several years have passed. Hiccup is now an adult, and he and Astrid have long been married and had children. Now, he, Astrid, and their two children are sailing alone on a ship, when Hiccup hears a familiar sound of flapping wings—Toothless is flying with me. Having grown accustomed to solitude and distanced from Hiccup, Toothless lands on the bow of the ship, his pupils narrowed with wildness.