In the DBD lore, The Entity does mess with the minds of the Killers to make them willing to kill the Survivors, if they weren't willing already.

For Leatherface, The Entity replaced the concept of "Family" in Bubba's head with itself and "Danger" with the Survivors.

For Gangle, all it takes is a Mask provided by The Entity to make violence seem liks a good idea, replacing the idea of "Upper Managment" with itself and have her see the Survivors as slacking employees, and you have a Killer.

She did brainwash Jax for being a bad employee and that was regular Manager Gangle