This is Sophita's Omega Sword from Soulcalibur IV. In the flesh. It's made not from polygons, but resin and styrene.

Buily by Harrison Krix, from Volpin Props, it's incredibly lightweight, and from his build log looks to have been as hard to construct as a real sword.

Sophitia's Omega Sword, Soul Calibur IV [Volpin Props]