Guards! Throw these miniscule vermin into the dungeon until they are of worthier size!
~ King Goobot

Gaolers (also called Wardens or Jailers) are known for keeping prisoners in check. These villains are feared for, or are known to, imprison their captives, whether it is in a jail cell, a cage, etc. For obvious reasons, the vast majority of these villains are Corrupt Officials. Many are also psychopaths who enjoy tormenting their victims by imprisoning them (e.g. Buffalo Bill from The Silence of the Lambs). Ironically, some gaolers can be prisoners themselves.

Gaolers qualify as Pure Evil if they imprison innocent people and torture their prisoners, such as Lots-O' Huggin' Bear who act as a penitentiary warden and breaks toys physically and psychologically by making Sunnyside a hellish place.