The attack patterns of robots and zombies are too similar. Just as the natural adversary of the ninja is the pirate, the natural adversary of the robot is the dog. So you should have a war between robots and dogs with a robodog as your main character.
Yes, and our hero and protagonist will have always felt more dog than robot, but will fall in a love with a robot, thereby confusion his loyalties (loyaltis being very important to both dogs and robots).
Bizarrely, there's an amazing Astroboy comic strip where the evil robot army's brains are all stolen from dogs. Confused loyalties ain't the half of it.
Oops...
Juliet