Rediscovering a Book Series

[Mulletmanalive]

I'm trying to find the name of a series of fantasy novels [there were 5 of them in the sequence] i read some time ago. The books were written by a woman.

I cannot remember the titles but they were about a Sorcerer [i'm pretty sure this was the term] named Robert, the girl who instantly proved to be better at magic than him naturally [I won't start on my usual rant on the subject] and his manservant, who i think was called Mickah.

The world was fairly generic, with sorcerers having been driven off by normal folk and hunted by the Guilde, and organisation that kept human knowledge and engineering ticking.

Robert had the ultimate spell of destruction, the Word of Destruction placed in his brain by the guardian of the Sorcerer's stonghold, a construct called The Key. The plot revolved around the Key being somewhat insane and a descentant of the sorcerers that caused the war in the first place trying to get the Word of Destruction from the Key. The girl, [Jen possibly] becomes the leader of the enclave and Robert inevitably falls for her [I said it was written by a woman...]

If anyone could help, that'd be great.