Dark Wizard Overlord is the mentor of Dark Apprentices. He's a 4-4 Dark Apprentice and the final boss of Dark Mana Cave. He has all abilities from them and carries a staff called Dark Wizard Overlord's Staff. All his attacks will cause 0.1% additional corruption within them. If the corruption reaches 100%, they will become controlled by him and attack other towers. After defeating him, you can get him as a free hero tower in every tracks.