Demons

Demons are shadowy creatures with no real mass or substance. Created by the Demon Lords in the Underworld (also known as Hell or Nilhel), they can pass freely between the inhabited worlds and the Between worlds.
They are invisible to most humans. They cannot cause physical harm, unless they have a body to possess. This could be a human, but possessing a human by force is not easy. Instead, demons seek to influence human behaviour by whispering in our ears, spreading lies and hatred. They feed on negative emotions, becoming larger, more substantial, and easier to see by animals and some sensitve humans who have the gift of Demonseeing.
Although demons have been given many classifications, there are two main types which can be divided into sub-categories. Higher demons, which have greater intelligence and include succubi, incubi, and vampires. Lesser demons, which include misery demons, malice demons, and mischief demons.
Lesser demons are the most numerous. They inhabit dark corners, waiting for a host. Everybody has at least one or two personal demons.
Misery demons are the ones that feed on our guilt and despair. They're the ones that whisper words that sap our energy and confidence. You're fat. You're ugly. You're stupid. You're useless. Nobody likes you.You're not good enough.
You may know those voices. We can learn to question the lies and negative thoughts they give us, and this reduces their power over us.
Malice demons are the ones that spread hatred, jealousy, and greed. They're the ones that incite people to hurt others through unkind words or acts of violence. They are the instigators of abuse, prejudice, division and wars.
People who have sold their souls to their malice demons become Ciphers. Ciphers have no visible aura and no visible demons because their demons live inside them. They can inflict huge damage to the world on a small, large, or world-wide scale. Think fanatics, serial killers, paedophiles, rapists. Hitler, Jimmy Saville, and Hannibal Lecter spring to mind.
Mischief demons are the least powerful demons and can be almost lovable, though unchecked they can create havoc. They hang around children a lot, though many adults have them too. They love teasing, pranks, and pratfalls. But if a mischief demon gets its way too often, it can develop into a malice demon.
The Shadowman is able to bind demons to his will, and uses demons to animate his creations, Gholems and Wraiths. In these forms, the demons can, and do, inflict mortal damage.