Immediately after the player claims the reward for Ishizu Ishtar's appropriate Character Unlock Mission, they will encounter Ishizu for the first time. She remains silent for a moment, before stating she didn't expect to ever stand on the "battlefield" again - something she did not expect from Kaiba. She then questions how she has her Millennium Necklace, having already given it to Yugi during Battle City, before she begins to wonder if this world has recreated the abilities she had during Battle City. Ishizu then wonders if this means Marik is in Duel World as well. She grows saddened, as she wonders if Kaiba has basically forced her to relive the horrors she faced back then.
Until the player manages to defeat Ishizu at least once, whenever they challenge Ishizu to a Duel, she says that she now understands that the player must defeat her if they are to proceed. She recognizes that this is her role in this world and prompts the player to defeat her in order to take control of their own destiny. However, she also warns the player that she will not make their Duel an easy one, claiming that the player will see that her strategies have no equal.
Until the player manages to defeat Ishizu at least once, whenever they lose to her, she announces that she won because her victory was never in doubt. She then offers the player a piece of advice: Although she has the power to see the future, that does not necessarily mean that there is only one, as the future can be changed. She reminds the player that they always have the power to change the future, and urges them to believe in their cards.
Upon Ishizu's first defeat, she will say, "Nicely done." She then tells the player that the path to the future is for them to choose, so they should choose wisely. However, she also tells them to not forget that she is forever a Duelist, as this means she may stand in their way again in the future. When that time comes, she says, the both of them should have an honorable Duel.
After the player redeems their final unclaimed reward for Ishizu Ishtar's Character Unlock Missions, they will encounter Ishizu again, who tells the player that she attained something in her previous Duel: the light of hope. She continues by saying that even if the future is overshadowed by despair, people have the ability to change the future. She admits she cannot foresee what awaits people in Duel World, but she will keep fighting for a brighter tomorrow, and that she'll battle using her cards (which includes the "Blast Held by a Tribute" card).
When dueling against Level 40 Ishizu Ishtar, these are the only cards that can drop; at lower levels, cards from the standard pool for Legendary Duelists may also drop.
In the Draw Phase, instead of doing a normal draw, recover 300 Life Points. This skill can only be used three times per Duel.
Level 4
Fairy's Smile
If you normal draw a Fairy-Type monster card during the Draw Phase, the card is shown to the opponent and you recover 1000 Life Points.
Level 13
Precognition
You can view the top card of both players' Decks until the end of the 5th turn.
Level 20
Gravekeeper's Lot
Can be used each time your Life Points decrease by 1800. In the Draw Phase, instead of doing a normal draw, draw a random "Gravekeeper's" card.
Drop
No Mortal Can Resist
Can be used when your Life points are at least 1000 less than the opponent's. All monsters in the opponent's Graveyard changes to Skull Servant. This skill can only be used once per turn.
Drop
Sealed Tombs
Until the end of the opponent's next turn, neither you nor the opponent can Special Summon monsters from the Graveyard. This skill can only be used once per Duel.
Drop
Dialogue
Character-specific
Seto Kaiba
When starting a Duel with Seto Kaiba, she says "Kaiba... I have already seen that you will lose this Duel to me."
When she wins the Duel, she says "Kaiba, there is no escaping your destiny."
When she loses the Duel, she says "Very impressive, Kaiba." followed by "You overcame your fate and changed the future."
Yami Marik
When starting a Duel with Yami Marik, she says "My dear Marik..." followed by "I will save you from yourself."
Card-specific
Monsters
When Ishizu Summons "Gravekeeper's Oracle", a cut-in frame of Ishizu briefly appears, and she announces "I shall play this card." followed by "Gravekeeper's Oracle."
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Oracle, attack!"
When Ishizu Summons "Gravekeeper's Visionary", a cut-in frame of Ishizu briefly appears, and she announces "I shall play this card." followed by "Gravekeeper's Visionary."
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Visionary, attack!"
When Ishizu Summons "Gravekeeper's Chief", a cut-in frame of Ishizu's face briefly appears, and she announces "Come forth, Gravekeeper's Chief!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Chief, attack!" followed by "Royal Rage!"
When Ishizu Summons "Gravekeeper's Shaman", a cut-in frame of Ishizu's face briefly appears, and she announces "Come forth, Gravekeeper's Shaman!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Shaman, attack!"
When Ishizu Summoons "Mudora", a cut-in frame of Ishizu's face briefly appears, and she announces "Show yourself, Mudora!"
Most of the time when Ishizu declares an attack with that monster, she announces "Mudora, attack!"
When Ishizu Summons "Agido", she announces "I summon Agido!"
Most of the time when Ishizu declares a attack with that monster, she announces "I attack with Agido!"
When Ishizu activates that monster's effect, she announces "Agido's effect activates!"
When Ishizu Summons "Gravekeeper's Assailant", she announces "I bring out Gravekeeper's Assailant!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Assailant, attack!" followed by "Stealth Slice Strike!"
When Ishizu Summons "Gravekeeper's Cannonholder", she announces "I bring out Gravekeeper's Cannonholder."
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Cannonholder, attack!"
When Ishizu declares a attack with "Gravekeeper's Curse", she announces "Gravekeeper's Curse, attack! Doomsday Purge!"
When Ishizu Summons "Gravekeeper's Priestess", she announces "Come to me, Gravekeeper's Priestess!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Priestess attacks!"
When Ishizu Summons "Gravekeeper's Recruiter", she announces "Come forth, Gravekeeper's Recruiter!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Recruiter, attack!"
When Ishizu activates that monster's effect, she announces "Gravekeeper's Recruiter's effect activates!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Spear Soldier, attack!" followed by "Lunging Spear Assault!"
When Ishizu Summons "Keldo", she announces "Come to me Keldo!"
When Ishizu Summons "Zolga", she announces "Come, Zolga!"
Most of the time when Ishizu declares a attack with that monster, she announces "Zolga attack!" followed by "Cape of Destruction!"
When Ishizu activates that monster's effect, she announces "Zolga's effect activates!"
(Voice lines found in game files but not currently not in game yet)
When Ishizu activates "Charm of Shabti"'s effect, she announces "Charm of Shabti's effect activates!
When Ishizu Summons "Gravekeeper's Ambusher", she announces "I bring out Gravekeeper's Ambusher!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Ambusher, attack!"
When Ishizu activates that monster's effect, she announces "Gravekeeper's Ambusher's effect activates!"
When Ishizu Summons "Gravekeeper's Commandant", she announces "Arrive, Gravekeeper's Commandant!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Commandant, attack!"
When Ishizu activates that monster's effect, she announces "Gravekeeper's Commandant's effect activates!"
When Ishizu Summons "Gravekeeper's Descendant", she announces "Come to me, Gravekeeper's Descendant!"
Most of the time when Ishizu declares an attack with that monster, she announces "Gravekeeper's Descendant attacks!"
When Ishizu activates that monster's effect, she announces "Gravekeeper's Descendant's effect activates!"
When Ishizu declares an attack with "Gravekeeper's Guard", she announces "Gravekeeper's Guard, attack!" followed by "Blazing Blade Strike!"
When Ishizu declares an attack with "Gravekeeper's Heretic", she announces "Gravekeeper's Heretic, attack!"
When Ishizu Summons "Gravekeeper's Nobleman", she announces "I bring out Gravekeeper's Nobleman!"
When Ishizu Summons "Gravekeeper's Spy", she announces "Arrive, Gravekeeper's Spy!"
When Ishizu activates that monster's effect, she announces "Gravekeeper's Spy's effect activates!"
When Ishizu Summons "Kelbek", she announces "Come, Kelbek!"
Most of the time when Ishizu declares a attack with that monster, she announces "I attack with Kelbek!"
When Ishizu activates that monster's effect, she announces "Kelbek's effect activates!"
Spells/Traps
When Ishizu activates "Blast Held by a Tribute", she says "I caught you!" then she announces "I activate my Trap Card! Blast Held by a Tribute!" followed by "The Tribute Summoned monster is destroyed the instant it attacks!"
When Ishizu activates "Cestus of Dagla", she announces "The Equip Spell, Cestus of Dagla!"
When Ishizu activates the effect of that card during her attack, she announces "I activate the Equip Spell, Cestus of Dagla."
When Ishizu activates "Gravekeeper's Stele", she announces "I activate the Spell Card, Gravekeeper's Stele." followed by "I add "Gravekeeper" monsters in my Graveyard to my hand."
When Ishizu activates "Hidden Temples of Necrovalley", she announces "My Continuous Spell activates... Hidden Temples of Necrovalley."
When Ishizu activates "Necrovalley", she announces "My Field Spell activates! Necrovalley!"
When Ishizu activates "Rite of Spirit", she announces "I activate my Trap Card, Rite of Spirit." followed by "I revive a "Gravekeeper" from my Graveyard."
When Ishizu activates "Spell Reproduction", she announces "I active my Spell Card, Spell Reproduction."
When Ishizu activates "Wonder Wand", she announces "The Equip Spell, Wonder Wand!"
(Voice lines found in game files but not currently not in game yet)
When Ishizu activates "Dragged Down into the Grave", she announces "You shall reveal your hand to me." followed by "I activate The Spell Card, Dragged Down into the Grave!"
When Ishizu activates "Exchange of the Spirit", she announces "Cards in our Graveyards will go to our Decks, and cards in our Decks will go to the Graeyard." followed by "I activate my face down card, Exchange of the Spirit!"
When Ishizu activates "Imperial Tombs of Necrovalley", she announces "I activate a face down card, Imperial Tombs of Necrovalley." followed by "I negate that activation!"
When Ishizu activates "Monster Reborn", she announces "I active the Spell Card, Monster Reborn."
When Ishizu activates "Null and Void", she announces "Discard the cards you drew." followed by "I activate the Trap Card, Null and Void."
When Ishizu activates "Swords of Revealing Light", she announces "I active this. The Spell Card, Swords of Revealing Light."
When Ishizu activates "Royal Tribute", she announces "I active the Spell Card, Royal Tribute." followed by "We discard all monsters in our hands."
Trivia
Ishizu is currently the only playable character who does not have a 3D monster Summoning animation.
