End the session somehow going through the portal.
Have the devils hunt them down and hitting them with AEO plane shift, where the target has dis and the others have a normal save?
Or have him whip players to do the same thing.
Or have him kidnap Ratyn's family member, or Gina Honeyflower.
The party will go back to town.
Whoever touches the necklace can have a vision of Isolde exploring the city with her gang and facing off the devils.
- During the fight, Isolde takes off the necklace, giving it to the dead guy to bring it back to Naomi if she doesn't make it back, as Isolde rushes the whip devil and shoves him and herself through the portal.
The other devil, Zackarie, will know of Aggma, having heard of her from Nastvan (her mentor)