Oyaji created it specifically for Naofumi as custom made armor which can give him agility and defence like a Chain Mail in preparation to his first wave of disaster.
The first version is made of cheap copper and iron with the add of some Usapiru and Porcupine hides and a few Pikyupikyuu feathers. The Usapiru hides made up the fluffy wool portion around the neck, while the chest area was comprised of a metal plate. The joints weren't connected by metal, but by the Porcupine skins. Putting the hand in, you could feel the Pikyupikyu feathers fully stuffed between the duel skin layers. It looked like the type of armor that bandit lords would wear and had a a wild vibe.