Warden Gaia Sotharr is a member of the Order of the Radiant Flame, and is charged with warding the City of the Dead in Sharn. She is Brelish, but her values align with the Church of the Silver Flame in Thrane more than with the Church of the Cleansing Flame in Sharn.
Gaia has been locked in a power struggle with the lich Gath for years. She frequently destroys his minions, but has thus far been unable to destroy the lich himself. They've been locked in this struggle for so long that Gaia isn't sure how she would feel if Gath was finally destroyed, his presence in the city gives her life purpose and something to strive for. It seems like Gath must feel similarly, as it's hard to believe a lich couldn't have killed a single cleric by now.