A One-Round Adventure for 1st - 3rd Level Characters
Crimson Codex Faction Adventure 2
From the introduction:
On his myriad expeditions throughout Khorvaire and Xen'drik in search of the portents and signs that became his interpretation of the draconic Prophecy, Ohnal Caldyn traversed the highest peaks of Eberron and plumbed the lowest depths of Khyber. One of those expeditions beneath the surface of Xen'drik brought him into the sphere of influence of one of the imprisoned daelkyr, a creature of brilliant insanity known only as Virulence.