Evil You is the shadowy 'personification' of the corrupted evil/darkness manifested in the Hero's mind. The shadowy monster, who was anthromorphised as a dark shadow, also has the power to copy the Hero's abilities and name exactly, almost like an doppelganger. Evil You first appeared in The Locker as the monster taunted the Hero and cast doubts about how to protect Aquella, and moreso how the Hero's true strengths also elaborates the Hero's mental weakness in their own nightmares (and also the mental-world).