Lucifer (Cinderella)

Lucifer is the evil-minded pet cat of the main villain Lady Tremaine, and the secondary antagonist of the Disney animated movie Cinderella.

Although Lucifer was not evil towards humans he was a monster to the many mice that inhabited the home, he was also a troublemaker who enjoyed causing mischief.

Lucifer is thus considered a minor villain and a henchman of sorts to Lady Tremaine (at least, he views himself as one) - the role of henchman becomes more pronounced in the direct-to-video sequels in which Lady Tremaine gains access to the Fairy Godmother's magic wand and transforms Lucifer into a twisted version of a coachman, thankfully this chaos was later reversed when the Fairy Godmother regained her magic and put a stop to Tremaine's madness.

Trivia
The true name of Satan is "Lucifer", which is obviously what this cat's name is based off of.