#and is closer to nihility. not necessarily an alter ego but maybe her unconscious or id or smth

[hitokiri-izou]

With the new information on Emanators, it's becoming more certain that Acheron is one. Emanators of the Nihility, or just Self Annihilators, lose a part of themselves when they unwittingly step into Nihility. Some lose their sense of pain and pleasure, become numb, or start to lose their memory. In Acheron's case it definitely seems to be her memory. Not that it's completely gone but it's unreliable at the very least. During her dance with Black Swan, one frame seemed to have IX the Nihility

Right afterwards, Black Swan is shown being pulled in

It's said that just seeing IX is enough to lose your sense of self, which is what I think Black Swan was facing when she tried to peak at Acheron's memory. There was nothing but an abyss though

Being a Self Annihilator is thought of as having been infected with Nihility and some try to cure themselves and others by working with the Doctors of Chaos. I don't know that anyone willingly becomes a Self Annihilator but if they do, the new info suggests that to do so would be to slowly lose your identity, body, everything and commit a sort of ego death.

Black Swan doesn't have a body and is comprised of memory. If she were to step so close to Nihility she would completely vanish.

This was probably the closest to death Black Swan has been in a very long time