Hook, Line, and Sinker!
Role Players fall into one of two categories: the kind that give some thought to the lives their characters had before the campaign started, and those that don’t. Those that don’t have given the GM a blank slate, which of course tells me that I can feel free to populate that person’s past with whatever I feel like laying on them. I’m not saying you should have that PC’s twin brother who can mind control said PC without a die roll show up at the start of every session and take over the PC’s actions every session. That gets old rather quickly. (Believe me, I know. I had one of those GMs) What I’m saying is that when you want the PCs to consider actually doing some incredibly risky or stupid things, and for some strange reason this time they aren’t, you should feel free to up the ante by imperiling an aged relative, former lover, or beloved pet that the player didn’t know their character had until you mentioned it during the session. This, if you have even semi-decent players, can add some spice to the session!
It can also ensure that you receive a back-story from said player at the top of the next session.
Then you have the players who provide you with some background information. This can be in the form of a list of people the character is related to, a short blurb about some memorable moment in their life, or a 1,000 page thesis on the character’s motivations. Some players are kind enough to actually bait those back-story hooks for you. Others are sure to tell you how they have no relatives, lived their entire life in a dark tunnel, and have never met anyone before the campaign started; or alternately give you every last detail about every person their character has ever met, including the doctor who slapped their butt at birth, and what all of these people’s motivations are. I have no doubt that those others have mind controlling twin brothers in their pasts. The thing to remember here is a key element of any story: Point of View.
It is important to let your players know, up front, that the events detailed in their back-stories are the events as seen through the eyes of their characters. They can feel free to give you motives for these events, but unless the character performed the actions those are possible motives. The character can’t possibly know what the actual motives for actions they didn’t perform were unless they happened to have been Awakened on the Mastigos Path at the time of the action.
Let’s take for example one of the characters in my Mage campaign. Let’s call him, oh, I don’t know… how about Damien. Yes, let’s call him Damien. Damien’s back-story says that somebody stabbed him in the chest in the middle of a New York City street late one evening. This near death experience caused his soul to Awaken. Damien is now determined to use his new found abilities to find out who tried to kill him, and why they left this odd looking brass knife sticking out of his rib cage. As GM, I’m perfectly fine with this element of his story. As a matter of fact, having read his story, I can come up with any number of people who might have been inspired to attempt to stab him to death. All the same, I caution him that the events in his history are described as they were seen through Damien’s eyes. It’s always possible that things are not quite as they appeared to Damien. Damien’s player actually seems happy about this (he didn’t know me very well back then), and tells me to go ahead.
This was his second mistake. (Joining the campaign happened first.)
I now have a free hand to decide that the stabbing was… an accident? Maybe there was some parasite on his chest that he couldn’t see because he wasn’t a Mage at the time. Maybe this unknown assailant was trying to save him! Maybe it was a case of mistaken identity. Poor Damien really isn’t some twisted Fae creature trying to hunt down poor innocent Changelings, he was just in the wrong place at the wrong time! Maybe someone thought it was time for Damien to Wake Up!
I can take what he thought was a case of someone trying to kill him, and totally twist it into something he never suspected – as long as it makes sense to the rest of the back-story. If it doesn’t make sense you’re cheating. In the context of the other events in this character’s story, and in the rest of the campaign world, does this motive make sense? If yes, go with it! Blow minds! You’ll be glad you did.