Supplementary information on the first floor: In FATE/ZERO (official novel), SABER relies on the medium AVALON to summon. The Einzbern family provided it to Kiritsugu, so as long as there is a medium, it can be summoned
The ideal land that is far away from everything and isolated from the world is also called Avalon. In the legend of King Arthur, it is not only the name of the scabbard of the King's Sword (Excalibur) given to King Arthur by the Lake Fairy, but also the name of the goblin. The name of the country.
Legend has it that before his death, King Arthur ordered Sir Bedivere to return the holy sword Excalibur to the fairy in the lake. After that, he told Bedivere that he would go to Avalon, the fairy country, to heal his wounds, and that he would come back when Britain still needs him. return.
In the FATE world, Utopia is the Elf Kingdom in the sixth dimension, and the name of the scabbard of the Holy Sword is Utopia (Avalon) far away from everything. It is not the Throne of Heroes and is insurmountable. In the Holy Land, none of the five major magics can interfere. According to legend, King Arthur finally arrived before his death, while other kings could only meet in dreams but never arrive.
Other heroic spirits can generally only be summoned once, but King Arthur is special, but it takes a long time to explain this specialness. In short, she has received special treatment from the leader of the heroic spirits, and can participate unlimited times until she obtains the Holy Grail. Unless she herself gives up participating in the Holy Grail War.