How unusual ... Demandred keeps asking Lan who he is, unwilling to believe that any third age person could have his skill with the sword. Then he wonders if Lan is Asmodean!

I was quite shocked to read that.

I definitely wouldn't think of Asmodean as skilled with the sword. It seems that Asmodean is the only likely reincarnation in Demandred's mind who can channel him. The other possibilities have all been balefired.

It seems like most or all of the male Forsaken were highly skilled with the sword.