Greeks have a few gods or goddesses that could fit that description. Nemesis would probably be kind of a fun discussion.
PC: Nemesis? What's he like?
NPC: She. Actually she's a bit different from what you probably associate with the name.
PC: Oh good. Because I thought we were all screwed.
NPC: Maybe not. I mean, she had a temple and everything. So not everyone that was ever involved with her got, slaughtered awfully.
PC: Right. With a rep like that I bet she's great at parties too.
NPC: Not really. She tended to come when Themis called her. Themis is basically "Lady Justice" to us, the blindfolded lady with the sword, only in the older depictions she didn't need a sword because Nemesis had her back. Those who broke the rules got punished. Come to think of it, that girl you shot? She didn't happen to be an ordained priestess performing an authorized rite did she?
PC: Uh... Maybe?
NPC: Right. In that case I take it back. You're screwed. Please leave swiftly and try not to bleed on my floor on your way out.
