I'm a pretty big fan of "corruption" pictures and stories, and I'd like to try running a game that's somewhere along those lines.
I'm still unsure about many of the details, and would like to get some input and ideas from my partner, but the general idea goes something like this:
You are some kind of corrupting influence, something that is weak by itself, but able to turn other victims to its cause. The exact nature of this corruption is up to you, but it would involve being able to spread to affect several people at once. I will take on a GM role, controlling all the uncorrupted NPCs that you are trying to take over. Note that I'm also fine with switching roles, with myself as the corruption and my partner as the GM. The RP will start right after you start corrupting one of the characters, although whether this is full corruption (giving you total control of the character) or only partial (you can direct her to an extent, but she's still largely independent) is up in the air.
I will note that since I'm a straight male, I'd prefer to focus primarily on corrupting the women. There will be men, of course, but I'd rather the story not focus on corrupting guys.
Some ideas for the source of corruption:
-Demons/succubi: Pretty straightforward. One player would be a succubus that's able to take on a human form or otherwise disguise her true nature. Eventually, she would be able to corrupt other girls in the village and transform them into succubi as well. Anyone transformed like that would be under the player's direct control.
-Parasite: Some kind of parasite is able to control its victim. This could go a couple ways; the parasite might be something small that injects itself into the victim, and perhaps has to capture other victims to bring them to a nest of some sort. Or, it could be more like a bio-suit, that takes the form of clothes. In this case, the player would only directly control the parasite, but could grow indirect control over others; the story would start right when it takes over its first victim.
-Possession: Some kind of supernatural entity is able to possess people, but only under certain circumstances - say, they must be brought to a specific location, or must be in a certain type of mindset. This could be either full possession, with the victim having no control over herself at all, or it could be only partial, only able to have slight influence over her or only control her under certain circumstances.
If this sounds interesting, toss me a PM or reply here.