This is left up to the player as much as possible! Killing in self-defense or for survival would likely carry only half the weight of killing in cold blood, but it would still carry some.

Being forced to commit an act or being mislead into doing so would fall more on the character that forced their hand, I would say!

But it all also depends on how the character in question perceives things. If they feel personally guilty for it, they can seek to atone for it regardless.

Does that clear things up a bit?