The wizard Mirabo was a master of many tricks: spells of finding and binding, blasting and burning, catching and cursing. He was also a master of misdirection who made a lot of enemies due to his inveterate thievery and blackmailing activities. That is why, after being forced to fight off a particularly persistent assassin one summer eve, Mirabo decided to magically switch places with that of his ever-present feline familiar. His cat preferred the arrangement, since in human form the cat could eat all the smoked herring it wanted and got to kick the dog with impunity; Mirabo preferred the arrangement because when a lightning bolt fries an ambassador in a crowded room, nobody ever suspects the cat.
Mirabo’s cat continues to wear a human form, spending most of its time sneering loftily and being mysterious (which cats do very well) while Mirabo himself wreaks sorcerous havoc unobtrusively from the sidelines as a furry feline. In cat form Mirabo can’t work some of the more delicate spellwork that requires intricate finger movements, but he’s developed a splendid new line of nasty curses that can be cast with tail-swishing.