Drusilla

Drusilla is one of three suspicious female monks encountered by the Avatar in the era of Serpent's Fang (the other two being Solaria and Rieya). She can be found offering 'helpful' advice to the Avatar outside Issik's Maze.

It is revealed at the end of the quest for the Silver Seed that all three are in fact working for the Guardian, and have been sent by him to prevent the Avatar from restoring the Tree of Balance.

Drusilla, along with her sisters, was killed by the Avatar and party when they attempted to stop this restoration.