A Creature of Serpentine Grace

This reptilian creature with a human female torso seems to have been the main guardian at the center of the The Labyrinth. When confronted with the party of adventurers, the creature seemed to know they had smashed her eggs elsewhere in the maze, and proceeded to pelt them with arrows, while its gaze bewitched her assailants to act on her behalf.
The creature was ultimately overwhelmed through the combined efforts of the whole group, who also managed to break her ensorcellment of Pyro and the others. After it was slain, its chamber was revealed to house the bodies of previous victims sent into the Labyrinth, as well as a well that then led the adventurers into Hades.