How to get Emil's heads again?

[Oyamai~]

I defeated the Emil boss in the dungeons, but did not collect the weapon from him and left there, overwriting the save. When I go back there now, there are no weapons there. Is there any way to restart this quest or get Emil's head weapon?

[Lord Darth]

There are only two options:
https://steamcommunity.com/app/524220/discussions/0/2592234299579675694/