Been thinking about HTTYD 3 recently (mainly about how much I dislike it) and man, it really is just the antithesis of the rest of the series isn’t it?
The whole franchise of HTTYD from the movies, to the specials, to the 2 TV shows is all about building the relationship between humans and dragons. It’s about them learning how to coexist and how to support each other.
1 was learning that coexistence was possible.
The first TV series was getting a deeper understanding on how to make coexistence work, and where it might not be possible in certain cases.
The second TV series largely built on this and also involved deeper conflicts with other human civilisations.
And 2 is basically the apex of everything they’ve learned. Where they’ve fully developed a symbiotic society for both people and dragons on berk and the only threats they really face at this point are from other, more aggressive and exploitative dragon users.
It ends with Hiccup becoming the chief of Berk and Toothless becoming the Alpha for the dragons.
That is until 3 comes along and basically says “coexistence is too hard, let's send every dragon in the world to a secret underground cave, sometimes the fight to exist is just not worth it and it’s better to roll over and give the oppressors and the extremists what they want”.
Which is a horrible message for the end of a series that largely revolves around how humans and dragons deserve to share the same space and that it’s possible for them to live harmoniously with one another.