Another option is to remove the Necro-Demons and replace them with Beetles. Nothing will change significantly because the politics involve not the Ghouls or Beetles, but the people working with them – Necro-Druids who live in swamps and oversee the monsters. This is the most aggressive faction because the monsters need food and venture into the territory of the living... But I'm too lazy to create a small Fly and a large Beetle, but maybe I'll do it later, I don't know. A big advantage of the Skull-Demons is that they are simple.
Another option is to remove the Necro-Demons and replace them with Beetles. Nothing will change significantly because the politics involve not the Ghouls or Beetles, but the people working with them – Necro-Druids who live in swamps and oversee the monsters. This is the most aggressive faction because the monsters need food and venture into the territory of the living... But I'm too lazy to create a small Fly and a large Beetle, but maybe I'll do it later, I don't know. A big advantage of the Skull-Demons is that they are simple.