The original masks of the Diabolus that are thought to have been produced by a super-ancient civilization. They use materials that do not exist on Earth, making duplication very difficult. It is known that seven exist in this world.
Other than the "Mask of the Divine Progenitor of Envy", which was recovered by Gambiel in Nara, the approximate locations of four of the six remaining masks have been found, so the financial power of the Round Table has promoted archaeological surveys of the relevant regions. Nevertheless, the second mask and on were not hard to find.
Yamato Tennoji, who was ordered to recover a Mask of the Divine Progenitor by Invidia, flew to South Africa and retrieved the "Mask of the Divine Progenitor of Wrath" from the Sterkfontein caverns. However, Yamato was fascinated by the overwhelming power of the mask...... And as if guided by the mask, Yamato found the "Mask of Lust" at the Carnac megaliths in France, and the "Mask of the Divine Progenitor of Gluttony" at the mausoleum of Qin Shi Huang in China. Yamato returned to Japan to find an owner suitable for the unearthed masks. Of the remaining masks that have not been found, one is said to be in the continent of America, but the location of the other two still remains unknown.
This is a different story of the unstable Black World. However, the Masks of the Divine Progenitor itself surely existed somewhere.