Editing Mai Valentine (section)

== Duelist Kingdom ==
Mai was invited to participate in the Duelist Kingdom tournament. On the boat to the island, she met Yugi Muto and Joey Wheeler and challenged Rex Raptor to a Duel, winning using her "aroma tactics" and taking Rex's luxury room.

Once on the Duelist Kingdom island, Mai watched Yugi's Duel with Weevil Underwood, initially doubting Yugi's chances of winning. She later Duels Joey Wheeler, using her aroma tactics to psych him out while powering up her "Harpie Lady." However, Joey exposes her "psychic powers" as fraudulent and wins the Duel.

Afterward, she wins a few off-screen Duels and is later challenged by Rex Raptor for a rematch. Not wanting to Duel Rex again but still interested in beating Joey, she proposed that Rex defeat Joey first. She reasoned that defeating Rex after he beat Joey would be like beating both of them.

Mai caught up with Joey and his friends and convinced Joey to Duel Rex. She became angry when Rex bet to win Joey's "Time Wizard," fearing it could be used against her later. However, Joey won the Duel.

Later, she shared her food with Yugi, Joey, and their friends, stating they could be friends that night but enemies the next day.

That night, Mai was targeted by Pegasus' eliminator, Panik. After losing all her Star Chips to him, she screamed, and Yugi and his friends came to her aid. Yugi challenged Panik, defeated him, and returned Mai's Star Chips.

Following Yugi's loss to Kaiba, Mai offered him her extra Star Chips, claiming she owed them to him. When Yugi refused, Téa Gardner Dueled Mai to win the Star Chips for Yugi. Mai initially dominated the Duel, but after Téa made a comeback, Mai, impressed by Téa's determination and eager to repay her debt to Yugi, surrendered so Yugi could have the Star Chips.

In the tournament finals, Mai was paired against Yugi in the first match. Initially, [[Yami Yugi]] was distracted by the prospect of facing Pegasus to win back the souls of Yugi's grandfather and the Kaiba brothers and did not take Mai seriously. Both Yugi and Mai helped Yami refocus on their Duel. Mai dominated at first, but by helping Yugi face his fears, she allowed Yami to make a comeback, leaving her at a disadvantage. When her strongest monster was destroyed, Mai surrendered rather than see her "Harpie" monsters defeated. With Bandit Keith's disqualification, Mai placed third in the Duelist Kingdom Tournament.

After her loss, she gave Joey one of her entry cards to prevent his disqualification from the tournament.

=== Legendary Heroes ===
Shortly after Duelist Kingdom, Mai Valentine was invited by The Big 5 to test a newly reprogrammed version of the Virtual Game built by [[Seto Kaiba]]. During this time, Yugi, Joey, and [[Mokuba Kaiba|Mokuba]] were searching for Kaiba. Along the way, Joey was forced to Duel Mai. Upon realizing her opponent was Joey (as both were masked), Mai joined the search for Kaiba.

During their journey, they faced numerous challenges: being attacked by a "Sand Stone" monster, getting trapped in a maze, fighting an army of Winged Beasts and Insect monsters, and ultimately battling the Big Five's "Mythic Dragon." Each of the Legendary Heroes needed to summon a Dragon-type monster to defeat the Big 5. Mai summoned her "Harpie's Pet Dragon" and sacrificed it to keep Yugi's "Black Luster Soldier" on the field, losing all her Life Points in the process. She was later revived by the "Mystical Elf."

=== Battle City ===
During the Battle City tournament, Mai won enough Duels off-screen to qualify for the quarter-finals. She helped Yugi and Joey's friends ([[Serenity Wheeler|Serenity]], Tristan, and Duke) by driving them to Yugi and Joey's Duel at the pier and shared her knowledge about the Rare Hunters, describing them as a group that lies, cheats, and steals rare cards.

Before the quarter-finals, Mai met Jean-Claude Magnum again. Initially not recognizing him, she remembered his earlier marriage proposal and her response to come back as a better Duelist. Magnum insisted on Dueling her again with the condition that if he won, she would marry him. Mai won, but Magnum tried to kidnap her in desperation using a hang glider. Mai nearly fell to her death but was saved by Joey.

In the quarter-finals, after Joey lost consciousness in his Duel with [[Odion Ishtar]], he dreamed about his friends, which helped him regain consciousness. When Mai asked if she was in his dream, Joey lied and said she wasn't, which infuriated her. Ignoring her friends' help and support, Mai proceeded to Duel [[Marik Ishtar]] in the next round.

During the Duel with Marik, Mai initially took the upper hand, even managing to steal Marik's Egyptian God Card, "[[The Winged Dragon of Ra]]," using "Amazoness Chain Master." However, Marik used his Millennium Rod's powers to transform the Duel into a Shadow Game (a "Yami no Game" in the Japanese version). In this version of the Duel, whenever one of Mai's monsters was destroyed, she lost the memory of a friend.

Toward the end, Mai was in a winning position with three copies of "Cyber Harpie" but attempted to summon "Ra." Unfortunately, the card appeared in Sphere Mode because Mai was not one of the chosen ones with the power to control it, and she could not read the Hieratic text to unlock "Ra." Marik used this opportunity to return "Ra" to his side by reading the text. As her feelings of loneliness returned, Yugi encouraged her to keep going. Joey rushed onto the field, trying to stop the Duel, and broke through to Mai, restoring her memory of him. Marik was shocked that their bond of friendship was strong enough to resist his powers. However, Mai ultimately lost to Marik.

In the English dub, Mai was sent to the Shadow Realm after losing to Marik. In the Japanese version, she was trapped within her own mind and subjected to severe mental assaults. After Marik's defeat, Yugi saved her. In the anime, she pretended to still be trapped in her mind, much to Joey's concern, but eventually, she revealed she was fine, laughing at Joey's worry.

After the tournament, Mai parted ways with Joey and the others, realizing they were her true and closest friends but feeling the need to move on in her journey.

=== Waking the Dragons ===
After the Battle City tournament, Mai Valentine continues her career in Duel Monsters, participating in and winning several minor tournaments. However, she finds herself overshadowed by Yugi, Kaiba, and Joey, and without her friends to guide her, she remains fearful of defeat. Mai is haunted by recurring nightmares of Yami Marik. In the dub, she dreams of being trapped permanently in the Shadow Realm by Yami Marik. In the Japanese version, she dreams of being trapped again, with Marik attempting to kill her while she helplessly calls for her friends to save her, but they never arrive.

Following a tournament win, Mai becomes frustrated when the runner-up and his friends make disparaging remarks about losing to someone like her, stating that she isn't a strong Duelist like Yugi, Seto, or Joey, who are seen as far stronger than her. In her frustration, she shatters the trophy she won.

Mai meets [[Valon]], who recognizes her as a Duelist who desires nothing more than constant victory. In the Japanese version, he wants her to stand by his side, promising to keep winning for her against anyone she desires. In the dub, he encourages her to forget her friends and gain power by joining Dartz's henchmen and wielding "The Seal of Orichalcos."

Under Dartz's influence, Mai is led to believe that Yugi, Joey, and her other friends have abandoned her. She particularly despises Joey, aiming to defeat him for herself. Meanwhile, Valon, who has developed feelings for Mai, believes Joey is the cause of her suffering and wants to take Joey down himself, though Mai does not agree with his plan.

Mai confronts Pegasus on Dartz's orders, ambushing and defeating him, thereby trapping his soul. Later, she saves Joey and his friends from a gang of bikers by throwing cards at them. While the gang doesn't get a clear view of their rescuer, Joey catches a glimpse of one of her "Harpie Lady" cards and a reflection of her in a helmet visor, leading him to suspect that it is Mai.

When Yugi, Joey, and their friends arrive at the Industrial Illusions headquarters to meet Pegasus, they instead find Mai, who locks them in. Mai challenges Joey to a Duel using "The Seal of Orichalcos," which puts both of their souls at stake. Mai initially dominates the Duel, but Joey begins to make a comeback after obtaining his Legendary Dragon. Just as it appears Joey is about to win (though he is actually aiming for a draw to save both of their souls), Valon intervenes, using his fragment of the Orichalcos to break the seal and save Mai. This infuriates Mai, who believes she had the Duel under control.

Valon decides to defeat Joey himself before Mai can Duel him again, hoping to protect her. Joey ultimately wins the Duel, changing Valon's attitude in the process. Mai arrives just in time to witness the conclusion of the Duel. Valon tries to convince Mai that Joey is a good person, but she is again possessed by the powers of the Orichalchos. She challenges Joey to a rematch, and he accepts, realizing that he cannot reach her until she is freed from Dartz's control. Throughout their Duel, Joey tries to make Mai see that Dartz has deceived her.

As the Duel progresses, Joey, exhausted from his previous Duel with Valon, begins to lose strength. Just as Mai is about to win, she has a moment of clarity, seeing through the deception and remembering their shared experiences. She decides not to declare her final attack and rushes over to catch Joey as he collapses. However, the Seal of Orichalchos claims Joey's spirit, as he no longer has the strength to continue, resulting in his loss. Devastated, Mai holds Joey in her arms and tearfully tries to stop the Seal from taking him. Before he loses his soul, Joey pushes Mai away and throws her fragment of the Orichalchos into the air. Joey's selfless act breaks the fragment, freeing Mai from Dartz's influence.

Seeking to repay Joey and Valon, Mai sets out to defeat Dartz and reclaim their souls. However, she is confronted and defeated by Rafael at their headquarters, losing her soul in the process. Rafael later saves her life by pulling her unconscious body from the wreckage of the collapsing headquarters.

After Yugi, Kaiba, and Joey defeat King Dartz, Mai's spirit is released along with Valon's and those of all the others who fell victim to the Orichalchos' ancient evil powers. Reflecting on Joey's kindness and friendship, Mai decides she is not ready to face him yet, feeling that she must "pick up the pieces" of her life but promises to make amends for her actions.

=== KC Cup ===
Mai spends the remainder of the series re-evaluating her life and trying to rediscover her passion for Dueling. In the dub, she mentions that she cannot face Joey and her friends until she can take responsibility for what she has done. She leaves her "Cyber Harpie" card with Valon, promising to return one day. However, in the dub, her relationship with Valon seems to have ended, and she does not explicitly state whether she will return to Joey.

Mai is invited to participate in the KC Grand Prix but only attends the final Duel as a spectator, where she watches Yugi defeat Leon von Schroeder. Although not actively involved in the final season's events, Mai appears briefly, such as when Pegasus considers her one of the Duelists essential to the Pharaoh's journey; she is seen sitting alone in her car, gazing at the clear skies. She is also referenced alongside Joey, Tristan, Téa, Kaiba, and Duke when Yugi reflects on how the Pharaoh helped him come out of his shell.

In the Japanese ending credits, Mai is depicted Dueling alongside Vivian Wong against the Meikyū Brothers (Paradox Brothers) on top of the Great Wall of China. However, in "Yu-Gi-Oh! GX," it is mentioned that the Paradox Brothers had only ever lost once, in their last Duel against Jaden and Syrus. This could mean that the brothers were either lying, as they often do, or that they defeated or tied with Mai and Vivian.