Yes, I'm aware that adding any form of communication with the dead in this game might be game breaking, but here's a though.
I'm not sure if it would be a good idea to add a town and a mafia version of this role (Psychic/Necromancer), so a Neutral/Benign Medium whose only goal is to survive until the end could work.
How does it work? You basically pick 1 player each night, and that player will be roleblocked. The roleblocked player will have no idea of what is happening, he'll only get a message saying something like "You were knocked unconscious and dragged to be used in some sort of ritual", or perhaps this could be an option (Possessed player can read ritual chat). Then, the medium will choose one dead player, and he will enter a chat with that player similar to the Jailor night chat. Whether the medium is anonymous to the dead player is also up for debate.
Thoughts?