Yes, there are likely some popular ones. For instance, some fanfictions that explore the relationship between Hiccup and Astrid during the time leading up to HTTYD 2 are quite popular. They might show how their relationship evolves and how they support each other in anticipation of the new threats in the second movie.
Some characters might be amused. For example, Hiccup, being the open - minded and curious one, could find it interesting to see how fans imagine different scenarios. He might even get some new ideas for his own adventures.
Fishlegs would likely have a very animated reaction. If he comes across some fanfiction that has really strange dragon facts, he'd be so shocked. He might start rambling on about how wrong it is according to his extensive dragon knowledge. His eyes would be wide and he'd be waving his hands around.
One interesting fanfiction could be about Toothless having a unique adventure during the time between the first and second movies that the other characters are unaware of until later in HTTYD 2. Another might focus on Hiccup's internal struggles as he anticipates the new challenges in HTTYD 2, all while still dealing with the aftermath of the first movie's events.
Fanfictions about watching HTTYD 3 in the past often focus more on the viewer's personal experience and how the movie affected them. Normal HTTYD 3 fanfictions usually center around the events and characters within the movie's universe directly.
The other characters like Fishlegs would probably be really into it. He loves stories and knowledge, so seeing different takes on the HTTYD 2 story in fanfiction would be like a goldmine for him. He might start analyzing the details and comparing them to what he knows from the real events.
Yes, it's possible that some Vikings enthusiasts might also be into 'How to Train Your Dragon' (HTTYD) fanfiction. Since both Vikings and HTTYD have elements of adventure, dragons, and Norse mythology, there could be an overlap in the fan bases. Some fans of Vikings might be curious about different interpretations and stories in the HTTYD fanfiction world.
No, it's not okay. 'How to Train Your Dragon' is a family - friendly franchise mainly aimed at younger audiences as well as general fans. Writing sexual fanfic related to it goes against the essence of the original work and can also be considered inappropriate and unethical.
A 'httyd visual novel' is probably an interactive storytelling experience set in the HTTYD world. It might follow the general plot of the HTTYD movies or deviate to create unique stories. For example, it could show what happened before Hiccup met Toothless in more detail. The visual aspect would enhance the experience, with detailed drawings of Berk, the dragons, and the characters. It may also have different endings depending on the choices made by the player.