The information here comes from the Sabriel Trilogy by Garth Nix. The books can be found in the young adult fantasy section of you local library or book store. If you have never heard of the Sabriel Trilogy, I would suggest that you go read that node before proceeding with this one.

"I have a variety of names. You may call me Mogget. As to what I am, I was once many things, but now I am only several. Primarily, I am a servant of Abhorsen." -Mogget in Sabriel by Garth Nix.

Mogget is an ancient free magic being bound to serve the Abhorsen by the red leather collar of charter magic and the Necromancer’s bell around his neck. In the first book, he is bound by Saraneth, the binder but in the last two he is bound by Ranna, the sleepbringer. When the collar is loosed, he must try to kill the Abhorsen because only when he kills his captor can he truly be free.

Even though he is bound to obey the Abhorsen’s orders, he generally tries to be as unhelpful as possible. Usually he appears as a little white cat with an odd shadow who needles his Master and mocks everyone who is around. He has also been seen in the books as an albino dwarf and his freed form, a twisting body of white fire.