Wicked: The Life and Times of the Wicked Witch of the West
Madame Morrible's robot friend/butler is often up to no good, and he (it?) is the one who murders Doctor Dillamond. What's interesting is that we don't really blame him for the deed – we blame Morrible. In fact, Grommetik doesn't really show any independence from Morrible until the very end of the book. Until then, he's just an extension of her. At the end we hear he's organizing a Marxist revolution. He is yet another part of the complex political fabric of Oz and perhaps a sign of things to come in the post-Wizard era.