A corruption mechanic is a common device of pen-and-paper roleplaying games in which player characters are prone to some form of physical, mental, or moral decay over time. They create a thematic game element that transcends the particular adventure or mission.
Fallout: New Vegas contains a complicated faction system that adds depth and complexity to Fallout’s sandbox world. Over time the player develops reputations with the various factions that have major impacts on the unfolding of the game. Examining this system provides a good set of guidelines for creating a faction system in any RPG sandbox world.
Since its earliest editions, Dungeons and Dragons has included an alignment system. Treated as a roleplaying aid, alignment is underutilized by most DMs and should have broader implications for the party and their world. The Fallout video game series is a strong example of how a character’s morality should impact the game world.