You are a patient visiting psychiatrist and telling your story. However you remembering some stuff differently than they were. Switch between your imaginary world and real worlds to complete levels.
The player is a ghost and is fighting to be the right hand of The Dark Lord. The one who brings enough hearts to The Dark Lord first will earn the right to be his right hand.
While holding the heart, the player cannot attack. The player can take over the heart from his/her enemy by hitting the enemy.