It's similar to the Ebony blade...
So it starts out with a pretty high damage, very slow swing speed, and superhigh weight (twohanded sword btw)
BUT it will increase its swing speed gradually (from 0.3 to the swingspeed of a 1H sword) as you kill enemies (not just friends)
Currently, I have a quest for it (trying to copy the Ebony Blade stuff a bit)
But I'm not really sure how to do the enemy kill count for the blade.
Help?