Re: Characters Losing Their Souls - How To Handle It?
This is a pretty cool idea. The price of power, even for doing good. It's a nice theme and one I like using myself.
The price is just right, the PC's soul. And yes, they should lose it. And it should hurt them. If you're into blue booking or heavy roleplay, have them wake up with memories they are unsure about.
A GM did this to me once in a Fantasy Hero game. My PC was a beserker who was melded with a demon. It had all kinds of upsides, such as fast, tough, very strong, healed fast, master at combat, etc, but the downside was he lost control, totally and became a driven killing machine until the demon had sated its lust for blood.
He gamed this out, with me in full control of the character. For him, it was a matter of knowing how I and my character would react. But you can manipulate how PC's react by how much information you give them.
The scene was on a ship, sailing to war, and I woke up in the middle of the night with something standing over me. It made a hostile move and I attacked it. A huge battle ensued, smashing through bulkheads etc. I was finally knocked unconscious by the monsters allies. When my PC woke, he was surrounded by the entire cast of PC's and NPC's, all bearing...remarkably similar wounds to those that I had inflicted on my 'demonic' attackers.
If your PC's are superheroes, they could retain control of their characters, but suffer a similar episode, where you describe a 'supervillian' attacking a 'bank'. They react as PC's do. Why would they not trust you as GM? After, they realise that it was a hero not a villain. One or two incidences like this, maybe even a severely injured normal, even a fatality if you want the angst, and the PC's are going to be asking questions.
Enter a mystic hero of some sort who points them in the right direction. To properly regain their souls, they have to reconnect with them in say, an astral realm they have been removed to, and this opens up chances for more roleplaying as they battle dark versions of themselves or whatever in order to aid their souls to escape whereever they are and return to their bodies.
Once that is done, there is a reckoning to be had with that mystic being.
There are so many ways you could handle it, but the theme shouldn't be the Ultimate Price of getting what you want, but should have some way out of it. Things shouldn't be easy, but it would be appropriately comic book to handle it in a manner somewhat like this. Arbitrary punishment or handing out of consequences such as "You die, don't make deals with the devil" are harsh and generally don't fit with the tone of most games.
Have fun with it, torture your PC's for quite sometime. Have them fearful of doing something to their DNPC's, put them on the run from the authorities for their actions, take away their bases, vehicles and support structures. REALLY give it to them.
It's an opportunity, if you will, to run a short supervillain version of your game, as the PC's succumb to being soulless and seek a way to redeem themselves and get their souls back. Big themes, grand storylines. Run with it. Sounds like fun.