Katoptron Katho Phlegon

The Gathered Straw Shall Burn Up Like The Moon
Rank: B. Type: Anti-Army noble phantasm. Range: 50. Maximum number of targets: 1 ship.
This is the optical weapon from ancient stories of Archimedes that was used to burn enemy warships on the shores of Syracuse.
Archimedes was little-known in Western Europe (the first comprehensive compilation on him was published c. 5-600 AD, enjoying a brief period of attention, but soon forgotten). It wasn’t until the literature and scholarly pursuits of ancient Greece were revived during the Renaissance that Archimedes would again be topic of the day. Of course, his weapon that could set fire to ships was of great interest to many.

One particular account stated: “After Marcellus backed his ships into the range of the arrows, the old man Archimedes set four mirrors of the same kind that were linked and moved with hinges in gaps that matched the size of the mirrors. The hexagonal mirrors he created collected the midday sun within them and shot out a ray of light regardless of whether it was summer or winter. Afterwards, when the sun beam reflected off of the mirrors, a terrible fire rose up on top of the ships, and then the ships that were within arrows’ reach all turned to ash.”

No method exists on today to burn a ship using only the reflection of a mirror, regardless of what kind of experiments are conducted. This is proof that Archimedes lived in a time when mana still saturated the atmosphere.
Archimedes had used magecraft to create a Mystic Code that absorbed mana in tandem with sunlight and fired it out as a heat ray.

Translator’s Notes
  1. ^ Official localization: Katoptron Katopregon.
Fate/EXTELLA material: Encyclopedia of Fate EXTELLA