Genuine lore question: how can there possibly be any 'evil' in the world if karma is tangible and explicitly apparent? Assuming that the existence of karma is universally acknowledged as fact, wouldn't people strive towards the boring 'good' side of things (charity, love, yadda yadda yadda) to become materially prosperous rather than take on the arguably more exciting illegal and greedy side of things?

Also, besides demons, how would we have inherently (or mostly) evil races like goblins and orcs?

Ditto especially for magic-users. What's a fantasy setting without an evil necromancer or sorcerer?