Lucifer

Lucifer is featured as a boss and Lady Tremaine's cat in Kingdom Hearts Birth by Sleep. In the game, Lucifer is on a self-assigned mission to keep Ventus and Jaq from collecting materials for Cinderella's ball gown, just as he did in the classic film Cinderella.

Kingdom Hearts Birth by Sleep
Cinderella (1950)

''Lady Tremaine's bully of a cat. He is constantly tormenting Jaq.''

Kingdom Hearts Birth By Sleep
Lucifer is shown sleeping in Lady Tremaine's room next to the last pearl (which he may or may not be guarding) for Ventus to gather for Cinderella's gown. As Ventus takes it and creeps back for the mousehole, Lucifer wakes up and prepares to strike Ventus from behind, but Jaq warns Ventus at the last minute and throws balls of string at Lucifer to distract him, but Lucifer rams himself into the cabinet where Jaq was standing, causing Jaq to fall onto the floor. As Lucifer prepares to kill Jaq, Ventus intervenes and strikes Lucifer's paw. Angered, Lucifer engages Ventus in a battle, which Ventus wins. Lucifer subsequently runs off and is not seen again.

Appearance
Lucifer is a fat cat with dark brown fur covering most of his body. The fur on his belly, his paws, and the tip of his tail is tan. The fur on his head is ruffled and black. Lucifer's eyes are green and his sclera are yellow, while his nose is pink. He has two whiskers on either side of his upper lip.

Origin
Lucifer is a ferocious cat from the 1950 Disney film, "Cinderella". A nemesis to Cinderella's mice friends and the other animals living on Lady Tremaine's estate, he is pampered and praised by the elderly lady. While the two stepsisters and the wicked stepmother fail to realize Lucifer's evils, he never manages to avoid the protective and watchful eyes of one person, Cinderella herself. She has a secret weapon used for dealing with the devious cat, however; her loyal dog Bruno. At the film's climax, he again tries to catch both Jaq and Gus while they are trying to free Cinderella from her locked room, but the birds see this and summon Bruno, who rushes to the mice's rescue and scares Lucifer out of the house.

Abilities
Lucifer himself has no special powers of his own, but he mainly attacks by using his claws. He is quite agile, able to leap from higher parts of the room to body slam opponents. He can also charge at Ventus if angered.

Trivia

 * Lucifer was the very first Disney Boss revealed to appear in Kingdom Hearts Birth by Sleep.
 * Despite his journal entry giving him the name "Lucifer", his name is never pronounced correctly in the game, to the point that even Ventus refers to him as "Roosifee", due to the fact that this is how Jaq pronounces it.