... Alright, I have an idea, finally. So we're going to focus on Berk a little after Hiccup's time, so we can have all original characters. Those born on Berk are expected to go to dragon training school when they reach age fifteen. The Berkians are wary of those not of Berk, as they tend to only bring conflict. When a rider not from Berk appears on the island, tensions are raised and a group of older Vikings go out and capture this rider. They question her about where she came from, and she refuses to answer. The fresh group of dragon trainers are curious of this girl, and she asks them to help her free the dragons in her homeland. And so the adventure begins....
This sounds really good i must say. I was half worried that this would end up as some kind of high school-ish centered roleplay only with dragons.
Though i feel like the "a group of older Vikings go out to capture this rider" seemed rather off honestly, if their wary of those not from Berk since their worried it would only bring conflict, i highly doubt they'd go hunting down a foreign girl who mind you probably also rides a dragon thus will not go judging The Berkians for having dragons as companions. I feel like they'd just kindly ask where she came from, not interrogate her.
Why not have just this. The girl came from a place that captures and imprisons dragons in a attempt to tame them and use them for war but sadly they do not know how to properly bond or care for dragons at all, however this girl maybe perhaps was just snooping through some chest or something and found a book about dragons that was made around when The Berkians were still at war with the dragons and allied with whatever place this girl came from (I would say
The Outcast but that wont really fit i say a new faction all together unless you have something in mind to make it work). The book is of course not the original Book Of Dragons but a copy that was given to them so they'd know more about the dragons they were dealing with and of course it doesn't have anything about how to care or tame dragons but does have info about them. (Though maybe when Berk started having dragons as companions they cut all contact with them)
The girl at some point finds a injured dragon (not a nightfury specifically but a dragon of your choice but i'd probably be best if it isn't a night fury), and through some hard work, and god knows how many bucket of fish she befriends the thing in which of course her village isn't very fond of but wants to force her to tame the captured dragons they have so they can be used for war in which she doesn't want to as she learned that dragons are not heartless, mindless giant overgrown lizards who do nothing but eat and breed. So she sets off to go to Berk in hopes of showing them that dragons are not the monsters they made them out to be but of course discovers that Berk is waay ahead of her.
So that's all i'm gonna type out for now ;p i feel like it's too long, of course you don't have to use this idea but it's just a suggestion.
Also i think to make things interesting that the characters besides the girl of course do not start out with dragons or have that much knowledge with dragons.
Also we should not have nightfuries, seriously i bet everyone is gonna have or want a damn nightfury.