At the end of the last story arc, I gave my players the chance to let their characters draw from a Deck of Many Things. I told them beforehand that this could mess up their characters and the whole campaign. They knew the risks and their characters knew too. Nonetheless, one character decided to draw a card, alongside with two NPCs.
And just as expected, the results were horrible and messed up the whole campaign. So the next story arc will focus on how the rest of the group deals with the problems. And they have a lot of problems now. But I found a way to link all those problems together, so they can go on an epic quest to fix everything.
Everything except one thing. A very important NPC (and member/sidekick of the party) drew the Balance card. I don’t like to define alignments for NPCs, so I decided that the card wouldn’t just change his alignment, but completely alter his personality. Before, he was funny, genuine and a little insecure. Now he’s serious, deceiving and confident. And the players hate it ^^. They want their old friend back.
So now I’m looking for a way to reverse the effect of the Balance card. I want to give the players the opportunity and chance to fix their friend. And this solution should be plausible and hard to achieve. I described the Deck of Many Things as this mystic and powerful artifact, which could change the world. So it shouldn’t be too easy to reverse its doings.
Are there any artifacts, spells, locations, events, deities, races, monsters or historical figures in D&D history associated with changing one's personality? We play D&D 5e in the Forgotten Realms Setting, but I’m open to suggestions from every edition or setting.
I know that there is a helmet that can change the alignment of its wearer, but I’m looking for a more permanent (and epic) solution. Some planes can affect one's alignment, but that’s not really what I’m looking for. And of course they could try to find another Deck of Many Things and draw the right card, but my players will never, ever draw a card from such a deck again ^^. (They’re not that stupid.)