In the first lands of lore there are two groups of monsters or creatures fighting each other and they both promise you rewards if you exterminate all the creatures from the other group which unless this is just a local thing is genpcide

There is no way without "cheating" such as but not limited to editing the game itself or editing the save files to complete the game without genociding to get to the next area

It was a different time back then genocide was acceptable and monsters were not human