The origin of the Necroa Virus in Plague Inc is a product of the game's concept. It was developed to introduce a new and exciting gameplay element. This virus is not based on any real - world virus in terms of origin. It's made to have features like the ability to reanimate the dead, which adds a lot of horror and complexity to the game. The developers probably got the idea from various zombie - themed movies and stories, and then crafted this virus to fit into the Plague Inc universe.
In this crossover fanfiction, the main characters might include a mutated pathogen from 'Plague Inc' that has gained sentience and a worm - hero from the 'worm' world. The pathogen is intent on spreading chaos and destruction in both worlds, while the worm - hero is determined to stop it. Their battles and interactions would drive the story forward as they both use their unique abilities and characteristics to either achieve their goals or thwart the other.
A cool plot might involve a scientist in the 'Plague Inc' world who accidentally discovers a portal to the 'worm' universe. As a result, the diseases in 'Plague Inc' start to mutate by incorporating the traits of the worms. Meanwhile, the worms also start to spread like diseases in the 'Plague Inc' world. Characters from both sides would have to figure out how to stop this strange crossover phenomenon before it destroys both worlds.
The origin concept of the Necroa Virus in Plague Inc is mainly for gameplay purposes. It was designed to be different from other viruses in the game. Inspired by zombie ideas, it has features like spreading through biting and creating zombies, which gives a new challenge to players.
One common theme is the struggle for survival. Humans have to fight against the vampire hordes that are spreading like a plague. Another theme is the transformation of society. The presence of vampires as a plague - like force can change how people interact and live.
The main theme is about the two dogs' struggle for survival and freedom. They are wrongly perceived as plague carriers and are chased. It shows their journey through the wild and how they face various challenges.
The main theme could be about addiction and the extreme measures to overcome it. In the story, there are likely some characters who are struggling with quitting something, and the 'quitters inc' might be an organization or a concept that is related to helping them, but perhaps in a rather unorthodox way.
Well, 'Interview with the Vampire' by Anne Rice can also be considered in a way. While not strictly a 'plague' novel in the traditional sense, the vampires in it are like a kind of 'plague' on humanity, with their eternal existence and the moral and ethical dilemmas they bring.