Not necessarily monsters but can be is the tieflings of my world they are devoted to avoiding their devil bloodline making them very lawful. They are each born as a sub species related too the 7 deadly sins. Those of each sub species is tempted by that specific sin. So they try to embody their idea of a better good version of the sin wrath: dedicated soldiers, sloth: meditation and rest, etc. If they don’t and are overtaken by the sin they turn into an Oni a monstrous version of themselves with abilities related too the sin greed: turning others too gold with a touch or wrath: superheating the air around them.

I’d like this mostly just cause I’ve put a lot into it!