The Bloody Valkyrie

Senketsu No Sen’otome (鮮血の戦乙女)

Upon arriving at the site, Ainz Ooal Gown commands Aura Bella Fiora and Mare Bello Fiore to separate from him. Since they are now equipped with the World Items: Depiction of Nature and Society and Avarice and Generosity, he orders them to scout the area for any interlopers.

Demiurge has returned to the Great Tomb of Nazarick, where he meets with Cocytus and Albedo. He asks what is going and learns that Ainz intends to face Shalltear Bloodfallen alone. Despite Albedo's confidence that Ainz will be victorious, Demiurge is afraid of the possibility that his master may be killed. He criticizes Albedo's acceptance of Ainz's decision, noting how she was most critical when their master went to E-Rantel to become an adventurer. 

Demiurge attempts to leave to assist his master but is stopped by Cocytus who was given orders from Ainz to prevent any interference. Demiurge relents, however, should Ainz fall he demands that Albedo step down as Overseer Guardian to which Albedo accepts, continuing to believe Ainz will return.

Ainz approaches where Shalltear is still in her standby mode. Seeing it as a good time as any, Ainz prepares for battle, buffing his stats with magic enhancing spells and arms himself with Quick-Change Items. Lastly, he prepares to cast the Super Tier Magic: Fallen Down. When the spell is completed, it causes massive damage, resulting in a gigantic crater where the Floor Guardian stood. Shalltear who had been calmly standing in a stationary position is not only armed with Spuit Lance but also donning her Valkyrie Armor. 

Despite looking relatively unharmed, Shalltear laughs and admits that the attack did some damage to her and she prepares to attack her master. The two exchange barbs and attacks at each other. Shalltear gains the upper hand, but Ainz manages to counter her using his experience and deception. Shalltear then summons her Einherjar, a physical double. Ainz manages to counter the two attacks and defeat the double, though he sustains attacks from Shalltear, with Spuit Lance draining his mana.

Eventually, Ainz uses Widen Magic: Cry of the Banshee. The area turns bright and as the light fades, the surrounding area having turned into sand. The attack leaves Shalltear unscathed. Ainz now low on mana, Shalltear prepares to finish him off. She asks if he has any last words. Rather than admit defeat Ainz declares that she was sloppy and that everything is going according to his plan.