The Magus of Illusion (幻想の魔術師 Gensō no Majutsushi) is the ka of Mahado, in the Yu-Gi-Oh! manga. This is the original depiction of the Magus of Illusion, known as the Illusion Magician, in the anime.
Magus of Illusion casts the "Curse of Illusion" on "Diabound
When the High Priests battled with Bakura, King of Thieves at the pharaoh's palace, Mahado summoned the Magus of Illusion to battle Bakura's Diabound. At one point, in the battle, the pharaoh, Dark Yugi left himself exposed, so Mahado prepared to protect him with Magus of Illusion. However Seto lacked confidence in the power of the Magus of Illusion and summoned Battle Ox, instead. Battle Ox managed to create an opening, which Seto instructed Mahado to use to attack Diabound. Magus of Illusion cast the "Curse of Illusions", restraining Diabound and preventing it from using its wall-phasing ability. The Magus and the other priests' ka continued to battle, which drained their ka, while Diabound remained relentless and broke free from the "Curse of Illusions". The Magus discontinued fighting after Atem ordered the priests to stand down.
Magus of Illusion was used in the High Priests' mock Diaha. Mahado tried to have it use "Curse of Illusion" on Seto's Duos, but Akhenaden summoned Dark Ushebti, which became the target of the spell. Duos attack continued, but the magus was protected by the barrier cast by Isis' ka Spiria. Magus of Illusion and its teammates were defeated by Duos, which had been strengthened by the sacrifice of its own teammates. After the battle, Seto called the Magus of Illusion weak and unfit to guard the pharaoh's tomb.