What is the mist?

The Mist is a magical mist that the gods and other magical beings can place over themselves to hide what they truly are from mortal eyes. This is why the world is generally unaware that the Greek gods and monsters are actually real. For example, a monster like a Cyclops might appear to them to be a tall human. In this story, a ventus manages to conceal his true nature by appearing to be a normal school boy called Dylan. The Mist was also used in order to send Jason to the Wilderness School, altering everyone's memories so that they would think they had always known him. The Mist even fools Piper into thinking she had a relationship with Jason. Demigods can be fooled by the Mist because they are half mortal, but Coach Hedge managed to see through it because he is a satyr and so a magical being.