Post a final boss game character that you find to be cheap, broken, AND overpowered

Most would choose Shao Kahn from Mortal Kombat... And that is what I am choosing :P

Okay, I can't name one with all three, but I can definitely give you one that is overpowered. Myrrah from Gears of War 3 on Insane mode is enough to drive anyone to drink! You have a laser-shooting bug as big as a house, fifty of her guards with chainsaw-guns, and Shriekers which are flying bugs with machine armas attached. It took four of the best Gears players among my group of friends to take her down. It took us about nine hours, and the only reason why we won was because the shriekers didn't spawn! Good God, that was awful. I also didn't get the achievement for it, so about two years later, I'm giving it another go. Wish me luck and good vibes.

The Mysterious Figure from KH Birth por Sleep is a ridiculously cheap and overpowered boss.

You're pretty much dodge rolling constantly while trying to get an attack in, and just one hit from him takes all of your hp except for one point. Not to mention later on in the battle he can literally turn invisible while still attacking. Wtf.
But so satisfying to defeat him I must say.

The guy in the vid is insanely good to defeat him in 5 minutes. It easily takes on average 20-30 minutos of trying not to mess up. One wrong mover and you can't recover from it.