I still wish they would pull a Soul Eater, with Sapna being not inside the sword, but being the sword. With the ability to revert to human form.
Bringing back the old, killing the young: that's the Marvel way
She kills several people in the Jean Grey solo with her sword.
I was more interested in the stuff around Sapna than Sapna.
Did they actually die though?
I believe the general writer consensus with the soul sword is it can counteract magical constructs, render organic beings unconscious, and (per Bendis) rip sentinels in half
It has changed so many times over the years it is hard to keep straight. I doubt there is a right answer.
They must have been magically created doppelgangers of people.