The Rocklands Beneath the Temple Ruin

From the introduction:

Long ago, a temple was built to the forgotten elven goddess Kalianis. A cataclysm struck and the temple was cast into ruins. A sacred statue to Kalianis sunk below the ground and was lost. The cataclysm also created a series of rocky tunnels beneath the ruin and in the fullness of time, an evil lamia named Xavi came to inhabit them. She gathered loyal followers to her and she uses these "rocklands" as a staging area for her raids upon civilization.