The Mirror Monsters (ミラーモンスター Mirā Monsutā^?) are entities created by Yui as drawings made by her and her brother when they were young and given life by Yui's mirror-self. As these creatures have no true life of their own, they prey on humans to survive on their lifeforce. The only human they cannot attack is Yui herself, whom they obey absolutely like Kanzaki. However, rogue Mirror Monsters who attack Yui are countered by Kamen Rider Odin or a loyal Mirror Monster who serves Kanzaki. However, the majority of the monsters are contracted allies and the power source for most of the thirteen Kamen Riders, building their power by absorbing the energy of other defeated Mirror Monsters, but if the energy is not absorbed, it reforms into a new Mirror Monster.