Just a night before Haruki's arrival at the Obsidian castle, Asuka, Athena, Alice, and Greta were all bound with a pair of enchanted chains of holy magic that deter the use of all dark magic. Not only that, it was made specifically to keep demons from shifting into someone smaller and escaping through the chains. And as if that wasn't enough, the dungeon itself didn't allow for dark summons, which was the only kind Asuka and the rest could summon.
Bound at hands and knees, they couldn't do anything to fight the carnal curse. Thus, huffing and puffing under their breaths, they laid there on the ground, their faces pressed against the mossy floor, withering away like an extinguishing candle.