is a character in Castle in the Air
She is a cat who Abdullah
and the Strangian Soldier
She is somewhat magical, but not a talking animal. ("Midnight" is just a name the soldier gives her, and is not her real name.)
She is pregnant when they meet her, and later gives birth to a kitten, which the soldier calls "Whipper-Snapper".
See also Castle in the Air (spoilers).