Nemesis (being)

Nemesis is a being of unknown origin, who is cursed with being permanently invisible. This forces him to wear a cloak at all times to remain slightly visible, but also gives him an advantage in rock-paper-scissors.

During a battle, he suddenly appeared, claiming to be the lord of darkness and hate. He summoned a hundred skeletons with armour and weapons, and gave them the power to control darkness. These skeletons were quickly defeated, and Nemesis retreated to parts unknown.