Lore

Bloody Valkyrie Incident

シャルティアの叛逆事件

World & HistoryBattles & Events

Vol. 3, "The Bloody Valkyrie," June–July of Year 1 after the transfer (day 12): mind-controlled by a Slane Theocracy World Item, Shalltear became Nazarick's enemy; Ainz defeated her personally and then revived her with gold coins.

While Shalltear was out, she encountered the Black Scripture, and Kaire (an old woman in a qipao) activated the World Item "Ruinous Beauty"; Shalltear was mind-controlled as she counterattacked, lost consciousness, and was left where she stood.
Back in Nazarick, Ainz confirmed that she had defected (her name had turned black in the management system, meaning a third party's mind control had made her temporarily hostile); Nigredo's scrying magic found her waiting in full armament.
As Momon, Ainz attended a meeting at the Adventurer's Guild, claimed the vampire was the "Honyopenyoko" he had been tracking, and showed a "Sealing Crystal" holding high-tier magic to win the right to hunt it alone; Igvarge insisted on coming along, ignored the warning that "you'll die if you follow," and was caught up in the fighting and died (he ran into Mare while fleeing and was killed).
Ainz tried to break the control with the super-tier spell [Wish Upon a Star] and failed, concluding that a World Item was responsible; he then entered the Treasury, met Pandora's Actor, and took World Items from the mausoleum.
In the final battle, Aura and Mare kept watch over the surroundings, with Aura borrowing the World Item "Scenes of Nature and Civilization"; Ainz finished Shalltear with the super-tier spell [Fallen Down].
Shalltear was revived in the Throne Room with 500 million gold coins as a medium; the control was gone, but she had lost her memories from after she set out (around when she parted from Sebas), and Ainz, considering it his own misjudgment, did not punish her.
After the incident, the Guardians were allowed to hold World Items to guard against unknown enemies; for "slaying the vampire," Momon's team became the Kingdom's third adamantite-rank team.
Only in Vol. 16, after capturing the Extra Seat and reading her memories, did Ainz confirm that the Slane Theocracy was behind it, and he resolved to destroy the Theocracy.