Soul coins in 5e Phb can give buffs a certain amount of times before the soul is released and depending on the soul can also offer insight into the real world like treasure spots, dungeon locations etc. The soul in the coin is unable to lie but cannot answer questions its living person did not experience. I think these coins could add some decent side quests in implemented correctly. They are quite a useful item in D&D. They are obviously used in the hells to trade for powerful items, favors and a bunch of other things.
I wonder if we will be able to return to the hells? That would be pretty cool expansion I guess.
