Arc 4The Great Holy Grail War
Mayuri left Singularity F for Chaldea after Olga Marie freed her from its Holy Grail, while Shirou remained behind to guard it. Mukuro Hoshimiya joined the Black Faction in the Great Holy Grail War, where her spatial powers helped turn back the Red Faction’s assault and made Jeanne identify her as the war’s greatest problem.
- Mayuri challenged Goetia with Leviathan, then used her Flaming Sword to shatter the Grand Temple of Time and returned to Fuyuki, where Chaldea withdrew without the Holy Grail.
- Olga Marie returned to the Great Hollow and used Medusa’s Holy Grail to bind Mayuri to a new anchor, then brought her to Chaldea while Shirou stayed behind to guard the Greater Grail.
- Darnic assembled the Black Faction’s Servants, including Mukuro Hoshimiya as Caules’s Archer, and the Great Holy Grail War began.
- Mukuro demonstrated her spatial gates and enhancements, sealed Heracles’s Mad Enhancement to help him care for an injured homunculus, and aided Siegfried during his clash with Karna.
- Mukuro’s spatial attacks helped the Black Faction fight the Red Faction, and she sealed Achilles’s Akhilleus Kosmos after Heracles held back its descending world.
- The Red Faction launched an assault from Semiramis’s Hanging Gardens of Babylon, but Mukuro redirected Karna’s attack into space and sealed the gardens’ flight, causing the fortress to fall apart.
- Amakusa Shirou escaped with the Red Faction’s surviving Servants, Mukuro sent Spartacus into space, and Darnic secured Fiore’s Command Spells after Vlad III’s death.
- Jeanne d’Arc arrived at Millennia Fortress and asked to see Mukuro, whose identity Jeanne could not fully read and whose presence she recognized as the war’s greatest problem.