Irbek stands among four heroes dispatched by King Leon thirteen years before the main events, tasked with locating the source of Kazan's Curse. His companions were warriors Aganzo and Roxy, alongside the war monk Barain Ranka. During this mission, the group confronted the demon Shiroko, who effortlessly overpowered them. Roxy ultimately defeated Shiroko by allowing her demon blood to spread completely through her body. This victory, however, proved part of Shiroko's calculated plan, as Kazan's Curse subsequently intensified across the land more powerfully than before, indicating Irbek's involvement in an event that inadvertently worsened the continent's affliction.