the Red Door, a metaphorical door that represents the subconscious mind, specifically the deepest, darkest fears and desires of an individual. It also the gateway to the Red Room," a physical space where individuals are trapped and forced to confront their darkest fears.
When someone is under the influence of the "Red Door" spell, they're forced to confront their deepest fears and anxieties, which can lead to a breakdown of their mental state or their awakening of their lucid.
Those who loose their minds are turned into fractured hollows or a source of any escalated trauma.
Then those who survive the door, becomes dream walkers, lucid humans with powers related to dreams.