Demonic woman inside a ring of fire

This being was encountered in a chamber within the Cave of the Sleeping Bogatyrs. The chamber lay at the end of a long passage to the left of a presumed doomstone near the entrance to the complex, which, as determined by Agapia signified the path a bogatyr would travel if he were seeking to marry. Inside the chamber was a high ring of fire, and faint, haunting singing could be heard from within. When Vorobei transformed into a hawk and flew over it, he saw a silken tent, and a woman, dressed in Rakhman-style clothing. The woman sang to him, took control of his mind, and forced him to attack his companions. When they rushed into the chamber, the woman rose up over the flames on dark, feathery wings, released Vorobei, and sang enticingly to Lokan, who rushed toward her, tried to kiss her, and fell dead upon the ground. She then called out to Yuri Barolov, but he had the presence of mind to reply that he was already married, and led his companions in fleeing down a passage on the opposite side of the ring.
After the companions returned from exploring the outlying chambers, they returned, and this time, the woman succeeded in dominating Yuri, and kissing him (though he survived). She then enticed him to walk through the ring, causing him to singe himself badly. Zorina and Agapia followed them inside, and while the ranger tried to heal Yuri and hold off the woman by firing arrows at her, Agapia managed to magically push her into the ring, thereby killing her.
The silken tent turned out to be held up by human bones.