Brought to you by Dead or Alive 4 (can you tell :l )

You stand atop one of the many skyscrapers defining the city's skyline, long hair dancing on an unseasonably cold wind. You subconsciously clench your hands into fists, stomach twisting slightly as the thing before you begins to fully materialise.

It is you, in every way that matters. Your skill, your knowledge, and from the looks of things it is quickly analysing your looks to take as it's own. A changeling, a shapeshifter of some kind. You watch as your own expression morphs into a sickly grin, showing far too many teeth. It steps forwards and you fall back into a defensive stance. This, at least, is one thing you understand; this is a kill or be killed situation, where the prize is getting to leave with your life.

You feel your lips turning upwards into a smile of your own as it rushes you, dodging a probably fatal blow to the temple and countering with several rapid-fire kicks to the temple.

It manages to evade all but the last, and how lucky for you that you've saved the best for last, and you send it flying towards the edge-

The creature stops just before, flipping upright and...floating, at least six inches off the surface of the building.
You feel momentary surprise before the excited anticipation hits. This, this is what you've been waiting for all this time. Your smile widens. The best kind of opponent for you, after all, is yourself.