In the international anime, the kanji on this monster's floatation ring is removed.
In episode 14, PaniK uses this card during his Duel against Mai Valentine. By using this card to obscure his monsters from Mai's view, he was able to easily destroy her "Harpie Lady Sisters" and defeat her. Later PaniK used this card during his Duel against Yami Yugi. After he summons this card, it got a Field Power Bonus due to it being played at night. Its effects serve as a barrier for all his other monsters and prevents Yugi from identifying what monsters that PaniK is using against him. In the next episode, Yugi activates "Swords of Revealing Light" to reveal PaniK's monsters for three turns. PaniK then activates "Yellow Luster Shield" to increase all of his monsters' DEF and switch them to Defense Position. Eventually Yugi uses "Catapult Turtle's" effect to increase the ATK of "Gaia the Dragon Champion" by 600 and Tribute "Gaia the Dragon" Champion" in order to destroy this card's floatation ring. Although it was still floating after this happened, Yugi deduced that his "Swords of Revealing Light" are now what is keeping this card afloat. After PaniK switched his monsters to Attack Position and ended his turn, the swords vanished, causing the castle to fall down on top of PaniK's monsters (they were unable to escape because of "Yellow Luster Shield" forbidding them from escaping). "Yellow Luster Shield's" last effect then inflicted damage to PaniK equal to this card's DEF, winning Yugi the duel.
In episode 16, this card can be seen in Kaiba's briefcase when he takes out a Duel Disk from his briefcase and tosses it to Joey Wheeler.
When used in the original manga, it had 1200 ATK / 2500 DEF, but received no bonus from the Darkness/Yami field. You can see it in the Original Print. They took that away when they made the card. In Duelist Kingdom, the bonus was an additional 30%. When you take away the 30%, it becomes around 923 ATK / 1923 DEF. These were rounded to its current value. Additionally, in the English dub, the Japanese manji is edited out. Despite this, the game Sacred Cards portrays it with the Duelist Kingdom ATK/DEF.
Castle of Dark Illusions made it so the opponent could not see your cards or Life Points, and made the opponent's attacks ineffective unless Swords of Revealing Light was in play. Also, if its floatation ring was destroyed, the castle would be destroyed and would destroy any monsters under the castle.
In the Spanish dub of the Anime, this card was known as "Castillo de las Ilusiones Oscuras".