Dayun was a member of the Imperial Navy's officer corps during the Galactic Civil War. He served as an admiral, commanding the Star Destroyer Implacable. In 0 ABY, shortly after the Battle of Yavin, Dayun informed the ship's chief engineer, Lieutenant Commander Del Meeko, that he had been reassigned by Admiral Garrick Versio, who had requested the engineer personally.
During the conversation, the admiral's normally florid face was outright flushed and he referred to Meeko by first name instead of rank, revealing how much the news had thrown the officer. Meeko subsequently departed the Implacable, with Versio inducting the commander into the Imperial Special Forces group Inferno Squad.
Dayun was mentioned in Battlefront II: Inferno Squad, a 2017 novel authored by Christie Golden.
Dayun was mentioned in Battlefront II: Inferno Squad, a 2017 novel authored by Christie Golden.