Granadian Crystal

A type of magical ore found sporadically around the outskirts of Granadia's capital. During the Demon Lord's battle against a massive army, his outflowing mana infused itself into the surrounding environment. It is valuable in forging blades but lacks the resilience to serve as core material, and the reddish parts actually increase fragility. No technique can separate the weaknesses from the strengths, so blacksmiths jokingly call it "the Demon Lord's Tear".