[Note: This is in response to a question someone posted on Reddit. You can see the original post here. (opens in a new tab)]

There can be different approaches, depending on the world the character lives in. Some ideas off the top of my head:

1) If they live in a world where being evil, good, or neutral makes a difference in their life in some way (some video games have this kind of mechanic), perhaps the character can stockpile “good karma points” by doing good deeds. This allows them to be marked as “good.” But this character is actually a villain or anti-hero, and after they stockpile enough good karma points, they go on a rampage of bad behavior, using up all the good points and returning to “neutral” status. This gives them the ability to wreak havoc without suffering the consequences of “evil” status.

2) A character keeps an internal tally of “karma points” on people they interact with. When someone reaches a threshold of evil karma points, the character’s weapon or ability activates, and they can punish the evildoer.