Slow Mutants are a form of humans that have been exposed to the pollutants of the Old Ones: mutated and bred. They have green skin that glows dimly in the dark, although in The Gunslinger Born they are shown as having human colored skin.
In The Little Sisters of Eluria, Roland encounters a band of them within the small town. They call themselves the Green Folk and are led by Ralph. The group beats Roland to the point of passing out, they also strung him up before he was saved by the Little Sisters. It is also revealed they have the ability to talk as displayed by Ralph.
In The Gunslinger, Roland and Jake encounter a group of slow mutants under the Cyclopean Mountains, after the Mohaine Desert. The slow mutants attack Roland and Jake as they travel along a set of railroad tracks in a handcart. The slow mutants display some intelligence by blocking the tracks with rocks. Roland is able to kill the slow mutants while Jake clears the track.
Roland once mentioned that a group of slow mutants had even infested the kitchens of Gilead after his world had moved on.
- Children of Roderick: The Children of Roderick retained a large measure of their humanity and recognize the authority of the gunslingers.
- Total Hogs: This group is rumored to be in possession of the blue bend of Maerlyn's Rainbow.
- Green Folk: The group in Eluria working for the Little Sisters (run by Ralph).
- Cyclopean Muties: The muties run by the Cyclopean Leader that attack Roland and Jake under the mountains.