Guilder
03-27-2019

Part of the Proof of Mythology (No.1) Memorial Album. This item drops randomly (and at times, rarely) from the mighty Minotaur, rumored to lurk deep within the Labyrinth endless dungeon.

You have a chance to run into this foe every 10 floors, but it's quite rare -- the Seeker of the Unknown title may help you find the Minotaur more frequently, though not by much.

Due to the Minotaur's elusive nature, I cannot presently confirm which version drops this item (the deeper you go, the more powerful it becomes, and its loot table changes depending on the version). Sorry about that, chief.

On to the item itself: it's apparently a consumable-type which works the same as the more easily obtained Ambrosia -- my digging into JP wikis showed nothing more noteworthy than that, though I'd imagine that due to how hard it is to find and defeat the Minotaur, this item probably has a stronger effect.

Sorry I can't be more specific here -- happy mythical monster hunting to you. Cheers.

Guilder
03-27-2019

Oh, right. For what it's worth, JP wiki suggests Minotaur floor 20-50+ versions have a chance to drop this. Your mileage may vary -- the JP wikis aren't always accurate compared with international servers.