Tweakers augmented through black market cybernetics and robotics until they are more machine than human. Their appearance is heavy on the shiny steel and visible augmentations and is meant to serve as a warning to others. They eat nanobots like they’re candy and are always high on something (usually LUN-1) sure to make them hell to deal with.
One Doom Roller is a handful but can be managed. Get two or three of them coming at you, and it’s usually best to run. Due to their insane nature, expect a change in leadership every few months.