Aileen Rao is a 19-year-old supermodel and dancer who serves as the main antagonist in episode 17 of Yu-Gi-Oh! Season Zero. She is a gaming addict who leads a double life challenging men to high-stakes games and humiliating them, taking away the things most important to them as they lose.
Aileen was first observed arriving at Domino Airport from a fashion shoot in Japan, where Seto Kaiba had summoned her in order to defeat Yugi. Aileen was picked up from the airport by world-renowned footballer Hirata, whom she later challenged to a game of chess (if he won, she was to go on a date with him; if she won, he would lose that which was most precious to him). Hirata was later seen being carried away on a hospital bed after losing the use of his legs.
Seto then introduced Aileen to Yugi via a video footage of a Shadow Game, inciting her interest in the boy. Rao then visited Solomon Moto's game shop in order to meet Yugi, where she signed a copy of her fitness video, which Anzu was in the process of buying, only to then reveal her identity after removing her sunglasses, causing Anzu to scream with joy. She then asked Solomon if he had any rare games which rely on skill rather than luck, before posing the question to Yugi regarding his favourite games.
Aileen then invited Yugi to find an interesting game for the three of them (including Anzu) to play in her hotel room later. After Anzu and Yugi arrived in her hotel room, she allowed Yugi to set up the game and showed Anzu (an aspiring dancer) her dance studio, before giving her some pointers and complementing her skill. However, Aileen then told Anzu to hold a pose, before putting a spell on Anzu that fixed her in that pose and also took away her ability to see or speak, before leaving the studio and locking Anzu inside. She then commented on the pair's naiveté to Yugi, saying that the only way to get Anzu out was to beat her in a board game called Raijinhai, or Anzu would remain frozen in that position forever like a statue. Aileen then revealed that she was one of Kaiba's game masters.
Yugi then transformed into Yami Yugi and agreed to face Aileen in her twisted game in order to save Anzu's life. After explaining the rules to Yami, she takes an early lead in the game (in which she has never lost). Over the coarse of the game, she played mind games with Yami, implying that she knew his every thought due to his predictable gameplay strategy. Part way through the game, Aileen revealed that her pet tiger was in the other half of the dance studio to Anzu, hidden by a rising door that was slowly opening (it would open incrementally every time Yami lost a piece. If Yugi failed then, the tiger would kill Anzu.
Seeing that his strategy was failing, Yami elected to abandon strategy, and play pieces at random, utilizing luck rather than skill, which seemed to offend Aileen. However, Yami had realized that, with her knowing that his picking of a random piece, the most ideal all-round piece for her to choose would be an elephant, and had planned his strategy accordingly, calling her bluff. By reading probability based upon their pieces, Yugi predicted each of Aileen's moves and began systematically taking out her highest powered pieces. Yami then revealed that Raijinhai had its origins in Ancient Egypt, and that within his mind he held 5000 years of Egypt's knowledge, before defeating her King piece, leaving Aileen in shock.
Aileen then accepted her defeat, and discussed the game with Yugi, as well as Aileen's mind-control abilities, before releasing Anzu from her spell. Aileen then concluded her dance lesson with Anzu, and parted ways with Anzu and Yugi on friendly terms, presumably after playing them at the board game Yugi had prepared.
Hours later, she reported her loss to Kaiba, who expelled her from the Game Masters. She then warned Seto that Yugi was stronger than he, and that he would never defeat him, only for him to cast her out of his mansion.
Aileen was last seen being waved off on her flight back to Paris by Yugi and Anzu, hoping some day to have a rematch with Yugi, and smiling at the concept.
Aileen reappeared in the final level of Kaiba's Death-T game, where she was placed in a remote control battle suit and forced to fight Jonouchi under the control of Ryuichi Fuwa, (Kaiba's second game Master) (Jonouchi was also forced into a battle suit and controlled by his friend Miho, in order to stop Jonouchi and Miho from saving Honda and Solomon from drowning inside a giant water-filling hourglass). The two battled for some time, before Aileen eventually drove Jonouchi's life points to zero, in theory ending the match. However, since Jonouchi remembered that he was not fighting alone and that he was "backed up by his friends hearts£, he was somehow (it was not explained properly) able to get back up and restore all of his life points. In his regenerated form, Jonouchi kicks Aileen hard in the face twice, draining her remaining life points and costing her the battle.