Im so tired of modern AU Toothless being a random stupid pet with no plot relevance. Like the dragons are so fricking smart. I think that in Cowell's books they actually have human intelligence? Yeah I prefer that WAY more than dragons as pets so in a modern AU without dragons, why not make them human???
And then I got to thinking and here are some ideas.
Human modern Toothless is a foster kid. His foster parent? The Red Death. Either he was raised by her along with the other dragons (Stormfly, Hookfang, Meatlug, Barf and Belch) or she ran like an orphanage where they all grew up. Obviously she's abusive as shit.
Idk how yet but Toothless loses his leg. Maybe it happened alongside Hiccup, in an accident or something, maybe it was caused by the Red Death? Toothless and Hiccup meet and become bffs. At some point, the Red Death gets arrested at some point for abusing the kids in her care, maybe Hiccup had something to do with it? There is potential to dive into prejudices etc about orphaned kids with Stoick, if you want to. You can make the situation of the orphanage/foster kids as realistically complicated as you want to, or not at all. I like to think that the core 6 get adopted into/fostered by the families of their riders. Hiccup becomes a bit cooler after hanging with the way scarier Toothless.
Of course you can also adapt the 2nd movie in a similar way. Valka returns, but she's made an enemy of Drago. Maybe she's an activist or something while Drago is an evil businessman (I know that's more Viggo's spiel, i cant think of anything better rn tho) Drago has connections and tries to get Toothless (and the others) away from their new families, and causes an accident that kills Stoick while putting the blame on Toothless. Of course Drago doesn't win, but Toothless is ✨️traumatized✨️ and Stoick is dead. If you want them to still be kids when this happens, Valka can get custody, but I like to think they're the same age as canon.
Anyway, here you have a solution so that Toothless doesn't become a dumb pet that could just be replaced by a fucking lamp and have the same importance <3