Pathfinder game in a home made setting.
These points represent dark deeds, and in turn often beget more dark deeds.
As with a hero point you can do many things, though the villain points are inverted. Allowing you to curse your enemies.
Each time you use one it turns one of your hero points into a villain points. If all your points become villain points your alignment shifts one step to the left.
The detailed functions of villain points will be given to any one that gets one. But otherwise those are dark favors that a hero has no business viewing.