Dark Bowser vs Omega Zero

Description
Fighting a final boss is cool and all. But fighting a final boss that is somebody who fights like an even stronger you is downright epic. So let's put two of my favorite final bosses that are stronger versions of the original and yet still lose to them. They both come out of nowhere with little to no foreshadowing, have badass fight themes, and fight you for their own master's reasons. They are so similar that I had to do this. Enjoy.

NOTE: If anybody has an idea for the pre-battle. I would highly appreciate it.