Large Basalt appear on floors 7 and 8 of the Marukyu Striptease within the Midnight Channel. They will be accompanied by a Liberating Idol and together they will use their Foul Breath skill while the Idol attempts to use Valiant Dance to Enrage the party, which will leave the party open to heavy damage from Physical attacks while being unable to strike the weaknesses of the Shadows. Upon being defeated, Large Basalts will drop the Tortoise Shell material. Selling 10 Tortoise Shells at Daidara will unlock the Masquerade ougi for Yukiko Amagi in the shop.
Large Basalt appears on floors 7 and 8 of the Marukyu Striptease within the Midnight Channel. While Light and Darkness are set as its weakness, the spells will have a lower chance than they usually would of connecting compared to other enemies weak against instant death spells. It may drop Lepidolite for trade at Shiroku Pub.