Karma (5e Variant Rule)
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This is a rule for DMs who want to keep players in line in terms of not constantly being murderhobos or taking a moment and thinking about the consequences of their actions. The DM has full discretion of this rule, though it can be insinuated through lore or hinted throughout the campaign environment as well for the players to have an inkling of it. This also is meant to replace the EXP mechanic of a campaign entirely, but you can have it alongside EXP.
The DM keeps track of a karma pool for the party. The party is not expected to know about this pool. There are no necessary numeric values. You simply need to keep track of limits for the pool, what is a lot, what is little, and what is a medium point.
- When players act in a way which the DM deems good, the pool increases. When they do something bad or evil, the pool depletes, all at the DM's discretion.
- While the players keep a relatively high level of karma in their pool, good things happen to them. Perhaps they level up or find free lodging, treasure, win a favor, etc. Low levels of karma cause bad things to happen, like a disaster to occur, blocking their paths, or their enemies suddenly appear stronger maybe. A middle level of karma causes a mix of minor good and bad events.
This is a very vague and general rule because karma is a vague and general concept. But for the most part it is supposed to make good things happen to good people, and punishment onto bad people. It puts a lot of power into the DM's hands. As a warning, since the DM is the judge and arbiter, it may sometimes feel unfair to players what the DM rules as good or bad.