Sherro was brought along by Ithaliss as a protector and servant on a mission to recover stolen artifacts from the abandoned ruins of Delenar. He hated the drow capitol of Shivass, and wanted to escape his life there - but that was not possible while Ithaliss alive, bending his will to her service.
Begging the heroes for a second chance, Sherro happily shared his skills both as a chanter and as a scholar, proving himself a useful informatant of the perils ahead of the heroes.