Ebony Blade vs. Promethium Sword

I'll admit i don't know alot about the Promethium Sword or really the Ebony Blade but 
the question is if the two exact clones were fighting with these two swords who would lose first
they have the same martial arts training assume they know everything about the swords and the best way to use them

The Ebony Blade is much stronger and versatile than a simple Promethium sword.
 
It's nearly unbreakable and able to slice through most materials, it possesses mystic qualities and is able to absorb/redirect magic.