I was running a D&D campaign for my son before and the two most liked NPCs were two goblins. One was a snivveling little companion who was actually a decent, though stupid goblin. The other goblin was a conniving, manipulative little shit that would backstab the group at any opportunity, yet they couldn’t ever bring themselves to kill him. Voiced them pretty differently with almost opposite personalities. It’s so great having characters that get that kind of reaction.