Devil Worm

Devil Worms are a parasitic lifeform that contaminated Earth after they were discovered frozen in the Pingualuit crater.

Overview
The Devil Worms were discovered in the Pingualuit crater in Canada, heavily implying their arrival to Earth via meteorite. Scientists who recovered the inert worms bought them back to Quebec city for study, but found that they were revitalised by the introduction of water. The Devil Worms breached containment and spread to the United States, contaminating both countries' water supplies. As a result, they began to infest the bodies of the population, taking control of them and turning them into cannibalistic creatures known as Ridden.

The Devil Worm infestation resulted in the collapse of Human civilisation, but was temporarily driven back by a specialist organisation known as the Cleaners, survivors tasked with protecting the remaining population and eliminating the Ridden. However, their efforts were undermined by a resurgence of Ridden aggression, including the extreme mutation of several Ridden and even the formation of biomass nests, from which infected bodies were reconstituted into larger, more powerful creatures. Due to the Devil Worms using the biomass of their hosts to create nests or more powerful Ridden, particularly those whose mutations seem almost strategic (Sleepers seemingly guarding enclosed areas, Snitchers and Reekers alerting other Ridden to the presence of prey, Hockers trapping survivors for other Ridden to finish off), the Devil Worms have been theorised to be actively cooperating with each other, possibly even connected in a hive mind. If true, this would explain the synergy of Ridden mutations and the formation of larger Ridden from multiple infected bodies, such as the Ogres and Abomination.

Ridden
Ridden are former Humans infected with the Devil Worms. They demonstrate heightened aggression, cannibalism and a complete lack of cognitive function, effectively being regarded as Zombies. The majority of Ridden maintain their human resemblance, but will actively attack uninfected Humans in hordes, demonstrating no regard for their own survival. These common Ridden also show physical differences from Humans through their pale skin, red eyes and the disturbances created by the Devil Worms beneath their flesh, sometimes even penetrating outside the body in spike-like formations. However, other Ridden undergo dramatic mutations, developing new inhuman abilities to make them more efficient killers.