Isn't that what the DO said to Demandred? Or something very close.

I think it is strange that everyone assumes the DO couldn't bring back Asmo, but I think it is more likely that he just didn't want to as punishment for teaching Rand.

Ditto for Osan'gar. He wasn't balefired, but not brought back either. I guess getting killed twice was one time too many for him. Again, he could have been brought back, but wasn't.

Now, nothing above relates to the limits of the DO's power in this area, but I'd think Balefire burns one out of the pattern, hence there is nothing to bring back. It's as if the person never existed. This is what leads to the pattern unraveling. It is also why the DO can't bring someone back.

As an aside. Isn't this what the DO and Ishy/Moridin want? I still can't understand why Ishy/Moridin just didn't run around balefiring everything, isn't destroyng the pattern what they both want?

Anyway, BF and Mashadar (would also consumes/corrupts the soul, in a way), and maybe that is it.