With the return of the dragons, and the rise of Dragon Hunters as a result, the need for Dragon Riders has never been greater. Hiccup and the rest of the original Dragon Riders have started training the next generation to fulfill their mission: ensure the safety of the dragons. A whole new set of Dragon Riders will be in charge of the safety of the archipelago. They will explore further and discover even more new dragons while protecting their home.

Dr. Hans Merwin began experimenting with combining human and animal DNA in 1984 with the hopes of giving humans the amazing evolutionary adaptations of other animals. However, his first attempts were not successful, and none of the human-animal hybrids grew to term. After years of extensive research and nearly-successful trials, the U.S. government took note of his breakthroughs and provided the funds he needed to produce the first successful birth of a human-animal hybrid in 1993. The team began testing the abilities of the children, sometimes taking extreme measures. As a result, in 2002, a hyena hybrid attacked the scientists and caused the operation to be shut down. The children were relocated to a large compound in Latvia to keep them separated from the rest of the world, and their creators. The addition of new hybrids to the compound leaves everyone to believe that the doctor and his team continue his work in secret.

This site I have less of a fleshed out idea for. This would be set in a post-apocalyptic era in Washington state after something killed off the majority of humans, but animals were pretty much unharmed. The animals from zoos and sanctuaries are now living in deserted cities and "wilds" of the state. Instead of playing as cats, characters would play as big cats such as lions, tigers, cheetahs, leopards, etc. There's a lot to work out with this site and this would require the most worldbuilding if anyone is interested in that.