Manga by author Ishida Akira

The setting of Fate/Apocrypha is a parallel world to Fate/stay night where the Greater Grail was removed from Fuyuki after the Third Holy Grail War and disappeared for many years. Around the 2000s, around the same time as the Fifth Holy Grail War would have happened, the group that plundered the Grail, Yggdmillennia, openly declares their secession from the Mage's Association and that they are in possession of the Grail. The Association dispatches fifty magi to retrieve it, but all but one are instantly slaughtered by Lancer of Black. The one remaining manages to activate the reserve system of the Greater Grail, allowing for the summoning of fourteen Servants in total.

After a long and treacherous journey, our Hero finally arrives at the Dark Ladycastle only to find himself being asked for help. The Hero explains how the war that the demons have brought upon the humans have killed thousands and put more in misery. The queen of demons however argues that this war has made the human society band together as one and showed empirical evidence how it has increased population, increased production, boosted economy and improved society overall. Furthermore, she explains to the Hero that ending this war will result in a civil war that will produce more bloodshed than there ever was. The Hero, convinced that the only way to bring peace, relatively speaking, is to join forces with the Dark Lady, agrees to help with her plans!

Typical high school girl Nanami is a descendant of demons. Sensing Nanami's hidden power is the Ministry of Sacred Treasures' first-class member, the demon slayer, Tomotaka. Though their initial meeting is as hunter and quarry, will Tomotaka's allegiances change when Nanami steps up to defend her against a more powerful enemy!?