The World Tree/Zorum

Zorum, titan of shadows, is the guardian of shadows created by Aluna as a gift for Nazuma. Zorum seeks to quench all light and obscure the senses and is depicted as either a black cloud or the shadow of Nazuma and has been tasked to protect her from her worshipers and to spy on the surface world in the night. Legend says that Zorum appears when a secret is told in complete darkness.