Ah, I thought u ran mordred lol. nvm (Why I recommended Osiris, didn't know ur soul was ur healer already)
I still think Osiris +15 burst gauge is quite handy though.. but yeah you probably don't need her right now
I was in a situation once where one of my members got incapacitated and nyarlathotep subbed in, i used amon's first and i think that usually lasts 4-5 turns depending on what fight ur doing, and i used nyarl's next and only 1 stack of stun got added in (and i think it only gave me 1-2 extra turns)
I don't recommend doing that though, if you decide to get Amon, you should probably put nyarlathotep on sub or take her out
I mean you can probably run her, but her only use would be the atk down, and that's about it.
lets say you decided to go use a team that is composed of Cassiopeia with BP/Lu Bu/Bastet/Nyarlathotep/Amon
your debuffs would be at 30atk/40def (you would be 40atk/50def if you have both yatagarasu and vine)
If you went with satan you'd still be stuck with 30/30 debuff for the time being until she gets awakened
If you decide to get Hades, and you went with the same team
your debuffs would be 35atk/30def (45/40 if you have yata and vine)
So overall I think you might want to pick Amon or Satan for the time being since they would increase your damage output