Well, although I knew that the people reading this book had probably played fsn, watched the anime, or read the novel. Still, I should probably make a statement just in case someone who had never seen any related works decided to get into it, right??
Glossary
Holy Grail: An omnipotent wish-granting vessel, a magical artifact capable of fulfilling wishes.
Holy Grail War: A battle fought over the Holy Grail. Seven Masters summoned seven Servants, and the ritual continued until one final victor emerged to claim the Holy Grail. It was held once every sixty years. Ten years after the Fifth Holy Grail War, the Greater Grail was dismantled, and the Holy Grail War should have officially ceased. But...
The Three Families: The three magecraft families that originally established the Holy Grail War system. Matou provided the system for controlling Servants. The Tohsaka Family provided the land and Leyline for the Holy Grail War, while Einzbern naturally provided the Holy Grail itself. Thus, in the Holy Grail War, these three families were often the first three to receive Command Spells and were known as The Three Families.
Servant: The means by which Heroic Spirits manifested in the world. Heroic Spirits were beings who had accumulated great achievements or fame in life, or possessed power capable of producing miracles. After death, they were elevated into Heroic Spirits, existing outside the timeline. Heroic Spirits could not be controlled by humans. Strictly speaking, Servants were similar to familiars; the vessels of seven Servants with different traits could accommodate the souls of seven Heroic Spirits, allowing them to descend into the world in a lowered state. Even so, the magical energy required for a Servant's manifestation was still terrifying, and they could only be summoned through the power of the Holy Grail.
Classes were the professions of Servants, divided into seven: Saber, Lancer, Archer, Rider, Caster, Assassin, and Berserker. Each class had its own characteristics. Magi were not people who changed playing cards or used props and tricks to fool the human eye, as ordinary people understood them to be, but humans who used magecraft. To ordinary people, Magi were basically wizards. The difference was that in the world of Magi, magic was a very strict concept, used only to describe grand magecraft miracles beyond humanity's ability to achieve.