|Patience of the Banyan Tree by Jackie Musto|
I am sure a lot of GMs has similar experiences with other systems and games. For me the Ravenloft Powers Check had an enormous influence on my tastes. I've spoken a bit about how it shaped my design, with things like Grims and Grim Beasts in Sertorius. Now I want to focus on how it showed me the joys of the dark and evil path.
A Powers Check is a roll made any time characters committed acts of evil in the misty realms of Ravenloft to see if the dark powers responded. Though the Power Check mechanics evolved over the course of the line's history, in their original incarnation they were a simply d100 roll, with a result of 100 indicating failure. The number could also be adjusted by the GM from 100-91, or 1-10%, depending on the nature of the act. On a failed Powers Check the dark powers respond by giving the character a reward and a punishment. There are six stages to powers checks in the original boxed set and as player characters pass through each stage the responses of the Dark Powers increase in intensity. So a character at Stage One might gain +2 Hit Points as a reward but develop an an "evil odor" of musk or decay. Slowly the changes become more noticeable and are reflected in the form of striking physical and/or mental transformations. Examples in the book include things like gaining Burning Hands but having your eyes melt away to your hands turning into tentacles and being able to foul food or water with a touch. By stage five the character becomes a creature of Ravenloft, at times possibly under the GM's control. By Stage Six the character is too far gone to the mists. He or she is ready to receive a Domain all their own and becomes an NPC forever. Such characters are Dark Lords of Ravenloft.
Powers Checks as they were presented in the rule book originally were double edged and in some respects, attempting to serve seemingly contradictory goals. They were a tool for warning "...players they [were] treading a thing line as role-players..." but also a way for the Dark Powers to "nurture" evil and "nudge [players] toward their 'welcoming arms'".
There were basically two types of GMs who ran Ravenloft, those who focused on the punishment aspect and saw Powers Checks as a way of guiding players on the moral path, and those who saw them as an interesting development. While I began as the former, I progressed into the latter over time.
I dove into Ravenloft head-first and never looked back. It was the setting that defined my early GMing experience. Powers Checks were a big reason why. I noticed pretty quickly that characters failing powers checks added something fun to the game. At first I saw them as dangerous fun, things that would come up occasionally but that you had to be cautious about. After a few years it wasn't a path I discouraged at all, I encouraged players to do evil things to warp their bodies and minds.
There were a lot of things about Powers Checks that appealed to me. Above all they were complete surprises. You couldn't really prepare for Powers Checks in advance because you never knew how a player would act in a given session. So when they came up, they are a response to in game developments by the GM, and they could drive the session in directions no one anticipated. In an age when railroading was somewhat the norm (and Ravenloft itself had its railroads) this was very refreshing.
Powers Checks also were a wonderful creative part of play. An important element of the Powers Check concept is the Punishment/Reward bestowed for an evil act, reflects the act itself and the nature of the character. This is a somewhat demanding requirement for an on-the-fly transformation of body and mind. So as a GM it was always a big moment because you wanted to get it right. It forced you to think creatively on your feet and I think that was both exciting and helpful.
More than anything though it was having a mechanic that made the the setting respond so tangibly to player behavior that made them so wonderful. For me at least, this transformative effect on characters was something new.
I think over time Powers Checks had a transformative effect on my GMing as well. I realized that evil characters were fully viable, they were a self-sustaining source of adventure potential.