I don't think there will be much killing just mainly he will be setting up the games and tell the rest of us what to do. Maybe if we start before we get in the house, he will talk to each couple as a random person to kind of setup why he chose everyone. The host will have to have a lot of creativity but also probably won't post AS much. I honestly don't know how this will work because I've never done a RP this big so I am completely open for suggestions.
Since we have 12 people, we might need to decide who is together or they can be single but get partnered together solely for the game, I'm thinking kidnapping in the same vain as Saw II.