(Note: This story is set after the end of the Race to the Edge series and before the second movie)
Hiccup Horrendous Haddock III is no ordinary viking. He is the son of their tribe's chief, and the one who ended the war against dragons. He also stopped the dragonhunters along with his friends, the dragonriders. But their war with the hunters is over now, the riders have left the edge, they are living normal lives now.
(Well, that is where this description would finish, but obviously it's not done yet)
Hiccup is a Haddock, one of the last, and the heir to a sacred power passed down from his ancestors. Now, a new enemy arises, and Hiccup must master the seven elements that course through him. His dragon's life depends on it, along with everyone else's.
You don't know how or why, but you've been isekai'd into the world of Jujutsu Kaisen. Although your first instinct is to stay far away from the plot, you've been blessed with an abnormal amount of cursed energy, and for better or worse, you find yourself sucked into the storyline. You decide that you may as well use your newfound powers for the greater good, and if you're lucky, you might succeed in rewriting some of the characters' fates. But it turns out that your presence in this world is even bigger deal than you first thought, and soon, everyone wants to make you theirs.