- For naval mission, see The Cerulean Lagoon.
Cerulean Lagoon is a location in northern Nagrand. During Yrel's training to become an Exarch, she is tasked with finding the source of the infection originating from the area, a mandragora named Plaguebloom. The infection was so potent that even nearby ship crews had to wear gas masks. After purging the corruption, the area heals.