The greatest video game villain of all time, Sephiroth is one of the medium's only evildoers (outside Bowser, anyway) who's almost a household name - so legendary was his tale in Final Fantasy VII, that Square Enix thought they'd carry his legacy forward with one of the most un-winnable and diabolical designs of all time. If you've played Kingdom Hearts you'll already know how its real-time battles replaced turn-taking, and how that increase in speed and reaction essentially pulls you into every fight. So take those base sensibilities and up the ante of what you're up against; a disappearing, occasionally-teleporting, brutally-effective soldier with area-effect moves that can reduce your health to zero. The last key ingredient in this stinky poop-sandwich is his attacks changing right near the close of the battle, where just as you think you've got a handle on his animation patterns, they randomise. Good luck keeping tabs on a guy who refuses to stay still or do the same thing in a defined order. If anything, this Kingdom Hearts' battle did a perfect job at redressing the balance on Sephiroth into a loveable villain who should also be feared and hated with the passion of a thousand burning suns. What's your most infuriating boss battle of the 2000s, and did you eventually win? Let us know in the comments!