The 'Heroes of the Hairy Hooligans' books by Cressida Cowell? The dragon Toothless there is a different creature altogether from the Dreamworks version. In the original books, he's a Common or Garden Dragon, essentially a tiny, brown, lazy, argumentative, and slightly useless reptile. His backstory isn't some grand myth; he's more like a stray pet Hiccup ends up with through sheer accident. He's not majestic, he's a terrible flier, and his main skills involve complaining and being a general nuisance. His 'origin' is basically being the runt of a litter Hiccup tries to train. The charm comes from their deeply dysfunctional, codependent friendship. Hiccup isn't a natural hero, Toothless isn't a majestic beast—they're both misfits who somehow make it work, with Toothless constantly threatening to leave but never actually doing it. The books build their history through small, funny misadventures rather than one epic flashback.
What's fascinating is how that dynamic informs everything. The movie's bond is based on awe and mutual respect; the book's bond is built on bickering, reluctant loyalty, and a shared sense of being profoundly underwhelming. Toothless's backstory is just... being a difficult little dragon. Yet, by the end of the long series, that makes his moments of actual courage or loyalty hit so much harder. You realize his bravado and selfishness are a cover for how much he genuinely needs Hiccup. It's a quieter, weirder, more literary kind of bond.