A glowing crystal found sporadically across Grand Gaia. Its faint glow isn't strong enough to light up the darkness, but it does emit magic of a unique wavelength together with the light it does produce. It got its name from the fact that Summoners could detect its power from quite a distance. To common people it is but a beautiful stone, but to the Demon Slayers it is a valued material.
Smoky-looking drops that release a putrid gas, found among clusters of special fungi.