After Cloak was sent from the Schamballa fortress in the northern Rockies, he reappeared in the mysterious apartment across from Philip Carlisle's apartment, bereft of his powers. Tyrone was then confronted by Avandalia, who told him to speak her name and then speak his. After he did so, she clasped his hand and said, "enough" (presumably accomplishing putting him under her spell). He reached out and touched her, then, with a sound if shattering glass, she crumbled away and vanished.
Avandalia ensorceled Philip Carlisle, bringing him to the mysterious apartment. She set a large dinner table, and the two waited for everyone else to arrive.
Detectives Nales and O'Reilly sought aid from Cloak, who had been staying at Carlisle's apartment. As soon as they approached, Avandalia called them over to her apartment, commanded them to speak her name, and then forced them to sit at the table, where a plate was covered with the faces of several tortured souls screaming for help.
D'Spayre arrived in the apartment (which had pulled free from the rest of the building and was floating in mid-air), and they discussed waiting for Cloak & Dagger, the former of whom would be their guest of honor. While they waited, D'Spayre transformed O'Reilly back into Mayhem.
Fleeing from Mephisto, Cloak & Dagger headed through a portal of light in a realm of darkness, emerging into the mysterious apartment, and Avandalia toasted their arrival. D'Spayre told them that the occasion was their last meal.
Avandalia took control of Cloak, forcing him to wrap his cloak around and contain Dagger. He apologized to Dagger, telling her he belonged to Avandalia. D'Spayre then took Cloak & Dagger on a trip, telling Avandalia to watch the other humans while he was gone. Avandalia asked Mayhem if she was enjoying the exquisite pain of Nales and Carlisle's withdrawal from the drug D'Lite, commenting that the withdrawal would be quite probably fatal..."unless, of course, I were to offer them some more D'Lite, which I won't, naturally." Just as Avandalia commented on how the combination of science and sorcery involved with Mayhem made her difficult to control, Mayhem flew forward, slashing Avandalia across the face with her claws. Avandalia screamed, " Noo oooo oooo " as she crumbled into dust.
Upon his return, D'Spayre was quite distressed to see the Avandalia had been destroyed. In a rage, D'Spayre blew apart the apartment they were in, but then told them that while he naturally grieved for her, the pain it produced served only to strengthen D'Spayre.
Avandalia is composed of some dark energy material which crumbles to dust when destroyed. She can apparently entrance and control others. She apparently can sense emotions (or at least pain), and she either feeds on pain or just really enjoys it. She has large, feathered wings and presumably can fly.