Legends of the Dreaming Sea
Aetaia is a sorcerously enhanced thrall, who is a passable terrestrial circle sorcerer herself, although she has only a very limited selection of spells.
Aetaia seems to be a “Silver Manticore” a group of thralls that had been enhanced to serve as sorcerer-warriors and assassins. The Manticores were wiped out nearly 200 years ago by the sorcerer-princes, amid accusations of infernalism and plots to take over Ys.
Their were no survivors and the rituals required to create them were destroyed.
She is a servant of Thegum the Eternal.