The Walking Dead: Daryl Dixon spinoff is exploring the concept of zombie variants and revealing their origins. These variants are infected by the Wildfire virus but have caught a different strain, giving them enhanced abilities. It has been shown that zombie variants are man-made and not naturally occurring. The creation involves capturing normal zombies and injecting them with something to enhance their skills. Additionally, decapitated zombie heads may play a role in creating the variants. However, it is unclear if this method is the only way or if there are other ways to create zombie variants. Hopefully, more information will be revealed soon.