The riddle of the Grail has always been, “Whom does the Grail serve?

selection of Masters for the Great Holy Grail War of Fate/Apocrypha.

She is the Ruler-class Servant of the Great Holy Grail War in Fate/Apocrypha.

The Church of the Holy Grail - a church dedicated to the legends of the Holy Grail

The open book upon the altar signifies obedience to God's word.

The Vulgate Estoire del Saint Grail (The History of the Holy Grail), about Joseph of Arimathea and his son Josephus bringing the Holy Grail to Britain.

The Subcategory Holy Grail is an imitation of the Greater Grail.

The Estoire del Saint Grail (The History of the Holy Grail), about Joseph of Arimathea and his son Josephus bringing the Grail to Britain.

Up until the third Grail War, the vessel for the Grail, also called the Lesser Grail (小聖杯, shouseihai?), was a literal "cup".

The Great Holy Grail War occurs after the Greater Grail had been stolen after the 3rd Holy Grail War.

To obtain the Grail requires asking a particular question at the Grail Castle.

Then Klingsor swore that if he might not serve the Grail, the Grail should serve him.

Klingsor then swore that if he could not serve the Grail, the Grail should serve him.

The vessel to the Holy Grail, known as the Lesser Grail, is used to summon the Greater Grail, which resides in the cavern underneath Ryuudou Temple.

This is beautifully expressed in the Holy Grail Legend where the warrior Parsifal discovers that question that unlocks the power of the Grail is not "Who does the Grail serve?" but "Who serves the Grail?