Gelish supports Elder Havva in serving the Temple of the Moon. In addition to being Head Disciple, he is also the Inheriting Disciple, the one to become the leader of the temple after Havva's passing. When Thorn arrives at his village, Gelish accompanies Elder Havva and questions the legitimacy of Thorn's title as Greymane. Though the title is legitimate, Havva challenges Thorn to a trial over the Greymane position, with Gelish fighting in his stead.

Gelish quickly finds himself outmatched by Thorn, but after dealing a blow to the titan, Gelish gives in to the corruption seeded within him by Karrandras the Betrayer. Due to this “Madness of the Moon”, the disciple grows immensely in power. However, succumbing to Karrandras's corruption disqualifies him from the trial. Hati blesses Thorn, and Gelish still finds himself on the defense. He gives in to the corruption even further, becoming a monster with barely any awareness. Several of the other disciples also give in to the blood lust within them. However, with the assistance of Elder Havva and Captain Del'har, Thorn cleanses the wolfkin, including Gelish. After these events, Gelish loses his status as Head Disciple and Inheriting Disciple to Thorn, and he and the other previously corrupted wolfkin are sentenced to confinement to meditate and reflect on their actions.

While still under discipline for giving in to the corruption of Karrandras, Gelish and the other wolfkin who had given in are summoned before Thorn and Elder Havva. They are informed that they are pardoned and reinstated into the Temple of the Moon, and Thorn returns the title of Head Disciple to Gelish. Furthermore, as Havva becomes more busy with his responsibilities as a member of Fang Valley's council, Gelish takes on the day-to-day responsibilities of leading the temple under the elder's supervision.