I don’t remember it ever being mentioned in Overlord. That’s more in the Dark Souls territory.
I was operating under the assumption that if you’re killed, then your soul lives on, but if your soul is destroyed, then you cease to exist entirely, and therefore couldn’t be resurrected, at least by normal means. That’s roughly how it functions in other works of fiction as far as I’m aware, but perhaps it doesn’t in this world.
It doesn’t specifically state that it can destroy someone’s soul, and if it did, I believe that Shalltear would not have been able to be resurrected, because there wouldn’t be anything to resurrect.
So I would say no, it can’t destroy someone’s soul.
Pertaining to your second question, the Goal of all Life is Death, with Cry of the Banshee simply had an AOE instant death effect, which could be countered by a resurrection effect.
Believe me, it could’ve been worse.
”Ainz could even use an unknown skill to temporarily boost his 1st-tier spells to the equivalent of 10th-tier spells.”
I got this from the wiki, but I don’t know exactly where it’s from. Also, I didn’t find anything about resistance to MP drain.
On behalf of R’lyeh, I thank you.
I like it.