Cardinal Koresh, a devoted follower of the Ovum Sanctum, joins the True Menagerie after narrowly escaping sacrifice at the Gate of Decay in Grimgate. His mysterious past, shrouded in the secrecy of his devotion to the Ovum Sanctum, hints at a connection to an enigmatic egg of otherworldly origin. Koresh's journey with the True Menagerie unfolds as they aim to prevent the catastrophic opening of the Primordial Gates.
 
In their quest, Koresh reveals little about his life before the True Menagerie saved him, maintaining an air of mystery. The group, aware of the presence of an unusual egg in Koresh's possession, remains in the dark about its true powers. Koresh's keen interest in a jar that emanates the scent of memories long past hints at a personal connection rather than a direct link to the ongoing events surrounding the Primordial Gates.
 
As the True Menagerie faces the challenges beneath the ancient ruins of Rhazidur and the failed attempt to save the Primordial Gate of Fire, Koresh's magical abilities and insights become increasingly crucial. As the party prepares for the imminent threat of the Primordial Gate of Storms, Koresh's role in their journey becomes pivotal.