Although it was a daunting task, the Empress and meta-alchemists discovered how to artificially breed prestoses, using a variety of substances and quasi- magical machinery to create and keep hatchlings alive. Although such prestoses are much smaller than the ancient ones and don't live long, their bodies still produce a protective lining inside of cocoons that is processed into the precious Arcalum. Entire hatchery is controlled by the Empress and can only be accessed by trusted servants, psionics and meta-alchemists.
A concept for my personal project called 'Absolutum'. The story takes place in a futuristic fantasy-like kingdom in totalitarian setting. The world, full of bio-engineering, meta-alchemy and psionics is ruled by the Empress, a quasi-immortal with powerful psychic powers thanks to her longevity and numerous mutations. The magical substance called Arcalum is the base of her power. Arcalum is used to run machinery and weaponry developed by royal meta-alchemists as well as a high-energy fuel source used in air-fregates. The rule of the Empress is eternal and unthreatened. Or so it seems.