It was a compromise between a number of people. I'm not that thrilled with them, either, but eh.

(Nor, for the record, was I ever that thrilled with Warrior and Witch. It was supposed to be titled Witch Hunt, which is also not brilliant but had a nice double meaning, but unfortunately another book at the same publisher had the same title and was going through the pipeline around the same time, so I had to change it.)

My favorite titles for the series, honestly, are the German ones: Doppelgänger and Hexenkrieger. They're parallel in a way the English could never really manage.