Marik's family guarded the tomb of the Pharaoh for generations and two Millennium Items (the Millennium Rod and Millennium Necklace) were passed on to Marik and his sister Ishizu Ishtar. Marik was forbidden to leave the Pharaoh's tomb due to his father's fear that the freedom and marvels of the outside world would further divert Marik's attention from his heritage. Marik no longer wanted to become a Tombkeeper, so his adoptive brother Rishid asked if he could take Marik's place but was refused. When Marik was forced to take the initiation ritual to become a full Tombkeeper, Marik spawned his second personality Dark Marik from the pain he endured. A year later, Marik and Ishizu took a forbidden trip to the surface but their father found out and attempted to kill Rishid. In the midst of his father's torture of Rishid, Marik blanked out and his second personality Dark Marik emerged for the first time to resist his father's punishment and claimed the Millennium Rod for himself. Ignoring his father's orders to put it down, Dark Marik used its powers to smash him against the wall. When Ishizu protested, she suffered the same strike. Dark Marik then proceeded to kill his father. After Dark Marik was sealed away in Marik's body by Rishid, Marik believed that the Pharaoh had ordered the loyalist Shadi to kill his father, due to Rishid saying Shadi had killed him, trying to be a big brother and hiding from Marik that it was actually his alter ego who had done so. This increased Marik's grudge and resentment to the Pharaoh, causing him to create the Ghouls.
As a teenager, Marik was the leader of the Ghouls organization as he wished with the Millennium Rod to obtain the three Egyptian God Cards so that he could unlock their power for himself, gain the title of "Pharaoh" and set his family free from the duty of the Tombkeepers. He also had a hidden agenda - to get revenge on the Nameless Pharaoh's soul for killing his father as he mistakenly believed that it was the Pharaoh's fault. Although he and his Ghouls uncovered "The Sun Dragon Ra" and "Slifer the Sky Dragon" from where Maximillion Pegasus had hidden them, they were unable to uncover "The God of the Obelisk", which was taken by Ishizu and given to Seto Kaiba.
During Battle City, Marik and his Ghouls hacked into Battle City's computer system and entered themselves in the tournament. After the Pharaoh defeated the weakest Rare Hunter, Marik used the Millennium Rod to take over the Rare Hunter's body to introduce himself to the Pharaoh. After the Pharoah defeated Pandora, Marik used the Millennium Rod to take over Pandora's body to introduce himself to Yugi Mutou, the Pharaoh's vessel. While arriving at Domino City, Marik used the Millennium Rod to have a Rare Hunter use Slifer against the Pharoah but the Pharaoh defeated the Rare Hunter and took Silfer as his prize. When he was getting ready to brainwash Jonouchi, Dark Bakura stood in his way, telling him to hand over the Rod. Instead, they made a deal where if Bakura obtains Slifer for him and defeat Dark Yugi, he would give him the Millennium Rod. Dark Bakura then stabbed himself in the arm and gave control back to his host, Ryo Bakura. He showed the injured Bakura to Jonouchi, Sugoroku, and Anzu, gaining their trust and taking the guise of Namu. While Kaiba and the Pharaoh dueled The Mask of Light and the Mask of Darkness, Marik used his Millennium Rod to brainwash Katsuya Jonouchi and Anzu Mazaki. After Kaiba used Obelisk to defeat Umbra, Marik used the Millennium Rod to take over The Mask of Light's body and brag about having Yugi's friends. Having a Rare Hunter hold Anzu hostage, the deadly duel between the Pharaoh and Jonouchi went through much to Kaiba's horror. In the midst of the duel, Yugi took over for the Pharaoh much to Marik's anger as he wanted to see the Pharaoh's demise not his teenage vessel's. When Marik forced Jonouchi with the Millennium Rod's full power, Jonouchi was able break free with his willpower.
Marik, Bakura and Rishid took places in the quarter-finals. Marik took the guise of Namu while Rishid pretended to be "Marik" as nobody had actually met him in person and known his true name (sans Dark Bakura, since although Anzu, Jonouchi, and Ryo Bakura technically met him, he pretended to be a boy named Namu). After Bakura was defeated by the Pharaoh in the first quarter-final match, Marik had Rishid use a counterfeit Ra card in his quarter-final against Jonouchi. When Jonouchi suspected that he was not dueling the real Marik, as Rishid had been dueling with honor while Marik was cruel, sadistic and as by far as Jonouchi was concerned, a dirty cheater; Marik ordered Rishid to use the counterfeit Ra to "show" he's Marik but Ra was angered by this and wrathfully struck both duelists with lightning, ultimately rendering Rishid and Jonouchi unconscious. After Jonouchi defeated Rishid, the latter reveals to the Pharaoh and Jonouchi that he is really Marik's servant while Marik began to suffer sudden headaches. After Rishid was further rendered unconscious, Marik revealed himself to everyone. Suddenly, Marik cried out in pain as his darker personality gained control of his body. While Ishizu dueled Kaiba in the fourth quarter-final match, Marik tried to call out to Ishizu but his dark personality trapped Marik in a "prison" built out of his own fear and pity. During his sister's duel with Kaiba, the Millennium Rod began activating on its own, causing Dark Marik to wonder why. Through Anzu's mind, Marik listened to Ishizu's story of how he became evil and created his darker side, thus beginning to reform himself. After the quarter-finals, his reformed soul confronted his other self, claiming that he would make up for everything he had done and apologizing to his father, before a Duel with him. In this Duel, Marik teamed up with Dark Bakura to stop him, but failed when Dark Marik used Ra's other abilities, which were unknown to Marik. However, Marik (through Anzu) warned Ishizu to hide Rishid from Dark Marik in order to save his life.
In the final duel between Dark Marik and the Pharaoh, their weaker selves were the victims of the Shadow Game being played. As the duel went on, Dark Marik became the dominant host of Marik's body while the real Marik's soul slowly faded out of existence. This Shadow Game gave him a clear edge, for when the Pharaoh lost Life Points, Yugi's body would fade away, and when Yami Marik lost Life Points, the original Marik would fade away. As Marik realizes his mistakes of making people suffer, he speaks out through Anzu, begging the Pharaoh for his forgiveness and asks him to defeat Dark Marik, even if it meant he would die. While they dueled, Rishid woke up and made Marik realize he had to accept his responsibility for being a Tombkeeper. With this confidence, Marik overpowered his evil self and made him the victim of the Shadow Game, and then forfeited, destroying Dark Marik. Marik gave the Pharaoh the Millennium Rod and the Ra card. Marik then revealed the Tombkeeper's initiation. The carving of the pharaoh's memory onto the back of a tomb guardian on his back. Fulfilling his duty as a Tombkeeper, Marik returned to Egypt to start a new life.
Marik, Ishizu and Rishid led Yugi and the gang to the tomb where Yugi and Atem must face for the Ceremonial Battle. Atem loses, so he passes on to the afterlife. He later escapes the collapsing tomb.
|VS — Ishizu Ishtar||Lose|
|VS — Dark Yugi
(through the Doll)
|VS — Yugi Mutou
(through Brainwashed Jonouchi)
- Takahashi, Kazuki (2002). "Chapter 1: Character Directory" (in Japanese). Yu-Gi-Oh! Character Guidebook: The Gospel of Truth. Shueisha. p. 66. ISBN 4-08-873363-0.