Kahrun is a revered Reian Elder who has a mysterious past and wields remarkable power. He used to be based out of the Sarpan Capitol, from where he led the Reian struggle against the Balaur. His Will is absolute and he forbids the fighting between Asmodian and Elyos.
At the start of the 3.0 update Kahrun saves the remnants of the defeated Elyos and Asmodian armies from complete annihilation by , and brings them to his homeland: Sarpan. He declares his "Will", which forbids infighting between the races, and tries to work together with them to defeat Tiamat and secure Siel's Relics. The presence of the relics however causes both factions to begin undermining each other and thereby the alliance as a whole. When the infighting causes the assault on Tiamat to fail he becomes infuriated, and later banishes all Elyos/Asmodians (bar the player and a handful of others) from his lands after he himself is betrayed by Empyrean Lord /.
After these events Kahrun leaves his throne in Kamar to search for a way to protect the Reian people by himself. His expedition is ill-fated however, and falls to repeated attacks from 's forces and an Ide explosion. Kahrun continues the search alone, but later is ambushed by the 4th Dragon Lord in the Idian Depths.
At the end of the Danaria Campaign (4.0) the player discovers Kahrun in the Infinity Shard, where it is learned that his parents are none other than Empyrean Lords Triniel and Nezekan. According to the book Legend of Eltnen 3, the birth of a child to Empyrean Lords was taboo, and explicitly punished by Aion himself. The Eracus Temple was thus created as a playground for Kahrun where he could grow up in hiding. The two Empyrean Lords discover one another again and try to help their son as they teleporting him out from the battlefield, then retreat.
In 4.7 the player meets Kahrun again in Levinshor. His condition is improving, but he has been troubled by vision that hints Beritra is up to something big. Kahrun points the player towards the Linkgate Foundry, where the Daevas learn of the Invasion.
There has been no mention of him since. His fate after the Upheaval (4.8) and Scarring of Atreia (6.0) remains unknown.