Fuyuki town was once home to a Holy Grail War that pitted Mages against Heroic Spirits. However, amidst the chaos, a sly Mage took advantage of World War II and made off with the Holy Grail. The Yggdmillennia family then adopted the Grail as their emblem and split from the Mages' Association, causing their wrath. Despite their efforts to challenge the Yggdmillennia family, the Association failed miserably. As the Holy Grail's system underwent a transformation, a colossal war unlike any other ensued.