system
Given the following post, respond as if you're commenting on Reddit:
human
[Dungeons and Dragons] Many of the greatest villains have believed that their actions were just. So, how does that effect their alignment? If a person does evil things, but with good intentions, are they good or evil?

As an example, from our perspective, ISIS seems chaotic evil.  But, they believe they're fighting to create a better world.  So, does that mean they're actually lawful good?  

Really, very few people view themselves as evil.  Most everyone thinks they're a good person.  So, how does alignment get applied to bad people who think they're good?
gpt
Alignment only work in multiverses in which there is an absolute definition for the extremes.

If, in yours, the definitions of good and evil are subjective, alignment must also be, which means that someone believing they are doing good will be good in their reference system, but not necessarily in yours.