Akrisae Kolluym is a priest and cleric of Saradomin. He is also involved in some fashion with the Temple Knights and is possibly a Temple Knight himself. He seems to be the Temple Knights' representative in the loose alliance between the knights, the Guardians of Armadyl, and the Crux Eqal, groups that are trying to hinder Lucien's evil schemes.
Akrisae is found in the White Knights' Castle in Falador, in the room with the jail cell in the eastern part of the castle's ground floor. During While Guthix Sleeps, Akrisae provides information and direction for the player. He also switches the player with Surok Magis later on. Interestingly, although he teleblocks the jail cell so that Surok cannot escape, players can freely teleport out of the cell after the quest.
Towards the end of the quest, Akrisae intercepts a spell from Sliske aimed at turning the player into the seventh Barrows brother, resulting in him taking the player's place, becoming Akrisae the Doomed (ironically, Akrisae was frightened of the Mahjarrat, though as the player states not all Mahjarrat are evil). When looting the chest in the Barrows activity, players may find some of his equipment.
Eventually, Akrisae would be freed of Sliske's control after the latter's death during Sliske's Endgame. However, he was not included in the quest, as the developers had forgotten that he existed. It is presumed that he stays with the Barrows brothers.