Ishizu is from a family of Tomb Guardians, tasked with helping the pharaoh recover his memories, when he returns. She works for the Egyptian supreme council of antiquities and possessed the Millennium Tauk, which gave her the power of foresight.
Ishizu became disconnected from her brother, Marik and the family servant Rishid, after Marik's hatred manifested into the destructive entity, Dark Marik. Ishizu aimed to defeat Dark Marik and save Marik at any cost. As part of her plans, she persuaded Seto Kaiba to host to Battle City tournament, despite foreseeing his failure in the tournament. However Kaiba defeated her in the tournament against her prediction. This made her optimistic that the future could be changed and she was able to convince Kaiba to help Dark Yugi defeat Dark Marik.
Ishizu recognized Dark Yugi as the pharaoh. She Marik and Rishid aided him in traveling to Egypt to conduct the Ceremonial Battle, to pass on the afterworld.
Ishizu came from a family of Tomb Guardians, extending back to the first Tomb Guardian, who served Pharaoh Atem's family. The family protected a prophecy foretelling the return of the pharaoh, who would be identified by his wielding of the stone slabs of the three gods. Ishizu's family also protected two of the Millennium Items, the Rod and Tauk for generations. Their duties involved passing the items onto the pharaoh in time, as they were necessary for him to reawaken his memories.
Her family lived in an underground tomb, with little connection to the rest of the world. Her parents needed a male heir to conduct the Rite of the Tomb Guardians and were immensely disappointed when she was born. When she was four, her brother Marik was born and their mother died giving birth.
Ishizu grew up on good terms with Marik and the family servant, Rishid. She and Marik, played Duel Monsters and Ishizu won at least one of their games, using a Deck–Graveyard switching strategy.
Ishizu stood nearby and prayed when the Rite of the Tomb Guardians ritual was conducted on Marik.
Marik, having never been outside yearned to see what it was like. He, Ishizu and Rishid made plans for him to sneak out. Marik faked a fever and pretended to be asleep. After their father fell asleep, he and Ishizu snuck outside, after sunrise for two hours, while Rishid stayed behind to take care of things. Ishizu showed Marik a street and explained what a motorcycle was, when Marik saw one in a book. Before returning to the tomb, they bumped into Shadi, who warned them that their fate would be a tragedy splitting their family, which was the will of the pharaoh. Ishizu tried asking Shadi who he was, but he disappeared among the crowd. Marik pointed out how Shadi's Millennium Key resembled the Millennium Items their family was guarding, but Ishizu reminded him that they were not to talk about those items in the outside world and insisted that Marik forget everything he saw outdoors, including Shadi.
When Ishizu and Marik returned to their home, Ishizu noticed a rope device that triggered when the door was opened, which their father had used to notice they had left. They found their father punishing Rishid, but cutting his back with a hot knife. Believing he had killed Rishid, he prepared to similarly cut Marik. However Rishid's impairment allowed Marik's alter ego, Dark Marik, to emerge. Dark Marik took the Millennium Rod and used its power to immobilize their father and pin him against a pillar. When Ishizu attempted to intervene, he similarly pinned her to a pillar. Ishizu realized that this was not Marik's true self and shut her eyes as Marik proceeded to murder their father and cut the skin off his back, which bore the Seal of Memories, and drop it on Rishid's back. Dark Marik was suppressed after Rishid regained consciousness. Ishizu stood by Rishid, as they watched Marik weep over her father's body and be told by Shadi that his death was the will of the pharaoh.
Ishizu regarded Dark Marik as the "devil, who brought tragedy to [their] family" and took it on herself to destroy him, and save Marik, even if it meant playing the bloodletting Shadow Games and using the power of the Millennium Tauk to cheat. For her crimes for which she was prepared to offer her life to the gods as punishment.
Ishizu became the secretary general of the Egyptian supreme council of antiquities. The council had been tasked by Maximillion J. Pegasus with hiding the three Duel Monsters God cards. Dark Marik's organization, the Ghouls, stole two of the cards, but Ishizu was able to keep one of them, "The God of the Obelisk", safe.
The Millennium Tauk gave Ishizu the ability to see into the future. She foresaw a turn-by-turn account of her Duel with Kaiba, which resulted in Kaiba's loss due to his use of "The God of the Obelisk".
Ishizu traveled to Japan to oversee the dynastic exhibit, The Art of Egypt. This took place in Domino City Museum and showcased stone slabs, depicting ka battles, from which Duel Monsters originated. She invited Seto Kaiba to the museum and showed him the slabs. Kaiba was astonished to see that the depicted nameless pharaoh resembled his classmate, Yugi Mutou. Although Ishizu claimed not to know who Yugi was. She told Kaiba about the God cards and tasked him with retrieving them from the Ghouls, through hosting a Duel Monsters tournament. To bait the Ghouls into coming, she gave him one of the God cards "The God of the Obelisk". Kaiba asked what if he acquired the three God cards, but refused to let them go, to which Ishizu replied that she trusted him. Secretly she gave it to him in anticipation of it leading to his defeat, after which she would reacquire the card and face Dark Marik later in the tournament, which she saw as her last chance to destroy him. She felt bad for deceiving Kaiba, but was willing to do what it took to save Marik.
With the Millennium Tauk, Ishizu predicted Dark Yugi would visit the museum. When he arrived with Anzu Mazaki and saw the slabs, she approached him. She told him that a great battle would soon be taking place and that he must gather the seven Millennium Items to regain his memories. Seeing Ishizu's own Millennium Item, Dark Yugi asked if she was an enemy. She denied being an enemy, but said that the enemy who was about to appear possessed the last Millennium Item, Dark Yugi was to encounter.
Ishizu took part in Kaiba's Battle City tournament and was the last to qualify as one of the eight finalists. She abstained from attending lottery selections determining the pairings for the quarterfinals, as she had already predicted their results.
Ishizu did not attend any of the first three quarterfinals, leaving her identity as a finalist a mystery to the other participants. Before the last quarterfinal, Kaiba expressed disinterest in the identity of his opponent, vowing to crush them regardless. However he was surprised when Ishizu was announced as his opponent. Ishizu informed him of the Tauk's prediction of the Duel and claimed Kaiba was inescapably fated to lose. Kaiba laughed at how she urged him to host the tournament to disband the Ghouls and now plans on defeating him, but admired her boldness. Kaiba regarded her claims as superstitious and declared that he would deal an iconic defeat with the power she gave him. Dark Yugi and Anzu also recognized Ishizu from the museum. Anzu wondered if the Tauk's prediction meant Ishizu's victory was guaranteed, but Dark Yugi said he would not succumb to fate, if he were in Kaiba's position. Ishizu's appearance caused Marik's ego to momentarily emerge, before being suppressed again by Dark Marik.
During Ishizu and Kaiba's Duel, Dark Marik recognized Ishizu's strategy as one she had used to defeat Marik. Ishizu glanced at Dark Marik and corrected herself on referring to him as "Marik", calling him "the evil thing that dwells within [Marik]". They silently communed via the Millennium Rod. Ishizu stated her intentions to defeat him and Dark Marik asked if she really believed it was possible.
Ishizu allowed Kaiba to send a large portion of her Deck to her Graveyard, via "Crush Card" and "Virus Cannon", after which she used "Exchange of the Spirit" to switch the contents of each player's Deck with their Graveyard. She continued to predict and counter Kaiba's moves. Finally, she allowed him to use her monsters as Sacrifices to Summon "The God of Obelisk", having secretly planted "Blast Held by a Tribute" in one of them. This would cause "Obelisk" to self-destruct on attacking. Kaiba prepared to attack, but reconsidered on being shown a vision of Kisara and a stone slab for The White Dragon. Instead he Sacrificed "Obelisk" to Summon "Blue-Eyes White Dragon", escaping the "Blast Held by a Tribute" and winning the Duel.
Ishizu congratulated Kaiba on changing his future and deemed him to now be the true owner of "The God of the Obelisk". She thanked him for showing her the light of hope. Knowing the future could be changed, she was hopeful that the despairing future shown by the Millennium Tauk may not have to be. Kaiba replied that a person who simply accepts their future has no light.
Worried about Mai Kujaku, who had fallen into a coma in her Duel with Dark Marik, Ishizu asked Yugi Mutou and his friends, if she could visit her. In Mai's room Shizuka Kawai was distraught by the suffering she had been witnessing. Ishizu informed her that war and suffering had been common for thousands of years, as past events repeat themselves, but people will still extend their arms eager to see the bright future they are hoping for. Yugi deduced that Ishizu must be Marik's sister and asked her why Marik was trying to kill them. She then told him of her family's tragedy.
While discussing the idea of Yugi and Katsuya Jonouchi Dueling, Shizuka suggested they ask Ishizu to look into the future to see who would win. Ishizu said that the Millennium Tauk had lost its power, since the future had changed in her Duel with Kaiba. She appealed for Yugi and Jonouchi to do what it took to return Marik to his former self. Fulfilling one of her duties as a Tomb Guardian, she gave the Millennium Tauk to Yugi, since he would need all seven Millennium Items to reawaken the pharaoh's memories. After Ishizu parted ways with Yugi and his friends, Anzu followed her and asked what would happen to Dark Yugi after the seven Millennium Items are placed in their slab. She replied that he will have a place to return to.
During the night, Ishizu was visited by Anzu, who was possessed by Marik. Marik asked her to help save Rishid, who Dark Marik planned on killing. Ishizu then moved Rishid's unconscious body to a different room.
The remaining rounds of the Battle City tournament took place in the Duel Tower. Ishizu remaining in the Battle Ship at first, watching over Rishid. While looking at the tower through the window, during Dark Yugi and Kaiba's Duel, Ishizu saw "Slifer the Sky Dragon" and "The God of the Obelisk" battling. She noted that the "Battle of the Gods" had begun, which she believed had been foretold by Tablet of the Pharaoh's Memories, and that Dark Yugi must win that Duel to regain his memories.
After Kaiba lost his Duel against Dark Yugi, Ishizu met him in the tower and asked if believed Dark Yugi could defeat Dark Marik in the finals. Kaiba replied that the probability was extremely low, but it was no longer his concern. He informed her that he planned to blow up the Alcatraz island and that they could leave on the Battle Ship before then. As he walked away, Ishizu told him that Dark Yugi needed his help. Kaiba was disinterested, so Ishizu asked if he had translated the prayer of the dead on the memory tablet. She explained that it was a dedication to the pharaoh, signed by his friend, Seto, who resembled Kaiba, but Kaiba remained unwilling to help. He commented on how Ishizu had planned on defeating him to save Marik from Dark Marik, but with the latest developments Dark Yugi was now her only hope. Ishizu said that he may be right, but she has long been prepared for the worst. Kaiba realized that she was willing to die, as the island self-destructed, if she could not save her brother. This reminded him of when he did the same for Mokuba Kaiba in a Duel. Kaiba then returned to the Duel field to give Dark Yugi the card, "Devil's Sanctuary", but claimed he did it to disprove the existence of miracles and the power of friendship.
During Dark Yugi and Dark Marik's Duel, Marik accepted that his father's death was caused by Dark Marik and not the pharaoh, Dark Yugi. He possessed Anzu to convey this message and that he was prepared to die for his actions, so that Dark Marik could be defeated. He apologized to Ishizu and asked why she had not told him the truth about their father's death. He figured she knew it was their family's fate for him to fight the pharaoh in Battle City. Ishizu said that the only fate she wanted for him was to keep living, even if he had become consumed by revenge. Unable to keep Dark Marik at bay, Marik reaffirmed that he must die in order to get rid of Dark Marik, despite objection from Ishizu. Marik informed her that the Duel was a Shadow Game, where either he or Yugi would be sacrificed to the darkness, if their other self lost. Rishid succeeded in helping Marik overcome Dark Marik and when Dark Yugi defeated "The Winged God Dragon of Ra", Ishizu was relieved to see Marik in primary control of his body, while Dark Marik had become the sacrifice. Marik surrendered the Duel, destroying Dark Marik, to which Ishizu thanked Dark Yugi.
Marik hung his head in shame, as Ishizu and Rishid approached him. Ishizu reminded him that their family had lived in darkness for thousands of years and said it had been his destiny to end that. She said that revenge should not last thousands of years or even a lifetime and suggested that their family may have been given the duty of guarding the pharaoh's memories, so that the pharaoh could teach them that lesson. Marik asked her if their family could live outside of the dark. She replied that she, Marik and Rishid were Tomb Guardians and family no matter where they live. Rishid, who had long yearned to be considered a member of the family was surprised and thankful to hear that.
To fulfill their duties as Tomb Guardians, Marik showed the Seal of Memories on his back to Dark Yugi. Ishizu explained that the depicted hieroglyphics contained the prophecy foretelling the pharaoh's return and the pharaoh could be identified, as he would wield the stone slabs of the three gods. With the God cards, being the modern form of the stone slabs and now being in Dark Yugi's possession, Ishizu said this was proof of him being pharaoh and that he deserved to know the truth of his lost memories.
Having conducted their duties and with their family reunited, Ishizu, Marik and Rishid returned to Egypt to start a new life.
After hearing that Yugi had collected all of the Millennium Items, with the exception of the Millennium Key and Scales, Ishizu sent mail to Yugi with instructions on where to go for Atem's final test, as pharaoh, and included a photo of the Door to the Underworld. Her distant relatives from another clan of Tomb Guardians brought the Key and Scales to the Shrine of the Underworld.
Ishizu, Marik and Rishid made plans for Yugi and his friends to travel to the Valley of the Kings by plane. However after Cairo National Airport was closed due to a sandstorm, Ishizu had the government provide a ship to take them across the Nile. She suspected the sandstorm may have a special meaning, since in ancient Egypt, it was believed that a ship was used to send the pharaoh and others to the afterworld. Marik and Rishid brought Yugi, Jonouchi, Anzu, Hiroto Honda, Bakura, Ryuji and Sugoroku to the ship, where they met Ishizu, who welcomed them to Egypt.
Yugi asked Ishizu about the photo she sent him. She explained that the depicted hieroglyphics around the Door the Underworld say how to open the door and sent the pharaoh's spirit to the underworld. She translated them as "Place the seven Millennium Items in the Tablet of the Pharaoh's Memories and use the pharaoh's name as the spell to open the door." and Marik informed Yugi that they also mentioned a Ceremonial Battle, which the pharaoh must lose in order to pass on.
The morning after the boat ride, Ishizu led Yugi and his friends to the Shrine of the Underworld and instructed Atem to place the Millennium Items into the stone tablet. The eye of the Door to the Underworld lit up and Ishizu explained that it would bare witness to the Ceremonial Battle and judge the truth of the pharaoh's defeat. She then witnessed Yugi and Atem splitting into two separate bodies to face each other in the Ceremonial Battle.
In the last turn of the battle, Yugi revealed he had "Monster Reborn" sealed in the "Gold Sarcophagus", preventing Atem from using that card to revive "Slifer the Sky Dragon" from the Graveyard. Yugi's friends were surprised that he sealed that card, because it also stopped him from using it. Ishizu suspected it was Yugi's message to Atem, saying that the souls of the dead must not linger in the world of the living.
When the Ceremonial Battle concluded with Atem's defeat and the Eye of Wadjet on the door began to react, Ishizu instructed Atem to say his name to the eye. With that the door opened. Ishizu felt sympathetic as Atem's friends made a final plea for him to stay, but eventually said goodbye. Once Atem left, the Tablet of the Pharaoh's Memories sunk into the depths of the Earth, along with the Millennium Items. The group promptly exited the shrine and Ishizu said that the role of the Millenninum Items had ended and the Door of the Underworld had closed forever.
|Agido (アギド Agido)|
|Keldo (ケルドウ Kerudō)|
|Kelbek (ケルベク Kerubeku)|
|Mudora (ムドラ Mudora)|
|Zolga (ゾルガ Zoruga)|
|Michizure of Doom | Fellow Traveller to the Grave (墓穴の道連れ Haka'ana no Michizure)|
|Revival Magic (魔法再生 Mahō Saisei)|
|Sword of Dogra | Sword of Dagla (ダグラの剣 Dagura no Tsurugi)|
|Blast Held by a Tribute | Bomb Held by a Tribute (生贄の抱く爆弾 Ikenie no Dakubakudan)|
|Exchange of the Spirit | Reversal of the Present World and Underworld (現世と冥界の逆転 Gense to Meikai no Gyakuten)|
|Muko | Invalid (無効 Mukō)|
|VS — Marik Ishtar||Win|
|VS — Seto Kaiba||Battle City||Lose|
- Takahashi, Kazuki (2002). "Chapter 1: Character Directory" (in Japanese). Yu-Gi-Oh! Character Guidebook: The Gospel of Truth. Shueisha. p. 68. ISBN 4-08-873363-0.
- Takahashi, Kazuki (2015). "Millennium Book – Chapter 6: Battle City arc" (in Japanese). Yu-Gi-Oh! Character Guidebook: Millennium Book. Shueisha. p. 152. ISBN 978-4-08-779722-0.
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- Yu-Gi-Oh! Duelist Duel 159
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- Yu-Gi-Oh! Duelist Duel 213: "Unbeatable?"
- Yu-Gi-Oh! Duelist Duel 214: "God's Sword, God's Shield"
- Yu-Gi-Oh! Duelist Duel 215: "Attack from the Darkness!"
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