holy relic

Kiritsugu and Irisviel went back to their own rooms, and opened the long box entrusted to them by the head of family. They were mesmerized by its contents. "Who would've thought... They were actually able to find this thing..." The usually composed Kiritsugu right now seems deeply impressed.

A scabbard made of gold and decorated with dazzling blue enamel. This sort of luxurious equipment should be called a treasure, to show dignity and nobility like a crown, or a scepter, instead of a weapon. Engraved into the middle is an inscription of the long lost Fairy Letters, proving this scabbard is not a work of man.

"... Why isn't there the slightest flaw? Is this really the genuine relic made from an era over one thousand five hundred years ago?"

"This thing is a type of Conceptual Weapon. It definitely won't deteriorate physically, not mentioning that it's a holy relic that will be used as a catalyst. This treasure lies in the realm of magic." Irisviel took out the golden scabbard from the lined box carefully, holding it in her hands. "Legend says keeping this scabbard on one's body will heal the wounds of its possessor and can stop aging... of course, the mentioned facts are magical powers provided by its 'original owner.’ Meaning as long as the Heroic Spirit summoned is functional, this thing itself can be used as a 'Master's Noble Phantasm.'"

The scabbard’s one-of-a-kind ingenious design and exceptional beauty entranced Kiritsugu, but in just a few moments, his train of thought immediately changed to the direction of how to use it as a pragmatic 'tool.'

- Fate/Zero: Act 1, Part 2