Heirorius was a male individual holding the position of lieutenant within the 204th Imperial Fighter Wing, a component of the Galactic Empire's loyalist military forces. Having dedicated twenty-two years to the Empire, Heirorius accepted an invitation to join the 204th. This recruitment occurred during the unit's attack on Dybbron III as part of Operation: Cinder; refusal would have meant death. Heirorius functioned as a comscan officer on the bulk freighter Yadeez and participated in the battle against the New Republic at the planet Chadawa.
Around 15 BBY, Heirorius began his service to the Galactic Empire, dedicating approximately twenty years to the Empire's military. By 5 ABY, he was stationed on the planet Dybbron III, which had seceded from the Empire's loyalists following the death of the Galactic Emperor in 4 ABY. In that year, the 204th Imperial Fighter Wing, under the command of Colonel Soran Keize and aligned with loyalist forces, aimed to devastate the planet for its defection. Prior to the assault, the fighter wing extended an offer of recruitment, which Heirorius accepted to avoid the impending destruction of Dybbron III.
Having achieved the rank of Lieutenant, Heirorius was assigned to a comscan station located on the bridge of the 204th's flagship, the bulk freighter Yadeez. The fighter wing then journeyed to the planet Fedovoi End, another world that had broken away from Imperial loyalists under the governance of the breakaway Yomo Council. Upon the arrival of the Yadeez and its escort ships at Fedovoi End, Keize transmitted a broadcast to the planet, and Heirorius frequently glanced at Captain Oratio Nenvez.
When the colonel inquired about a response from the planet, the lieutenant reported the absence of a reply, but noted the presence of energy spikes, suspected to be ion cannons being activated. Subsequently, Keize instructed the bridge crew to relay orders for 204th assets to initiate the attack. This resulted in the 204th shattering Fedovoi End's ice caps, releasing gas pockets and poisoning the atmosphere and its inhabitants.
Soon afterward, the Yadeez and its escorts were pursued across several star systems by the New Republic refitted Star Destroyer Deliverance and its starfighter wing. The 204th vessels eventually reached the ancient, artificial ocean world Chadawa, another target due to its secession from Imperial loyalists. During the 204th's attack, they sought shelter beneath Chadawa's network of mechanical planetary rings, sabotaging radiation-channeling radiation satellites while the Deliverance's wing engaged the unit.
During the engagement, Heirorius was at his post when Starfighter Commander Wyl Lark from the Deliverance's wing established contact with the 204th. The lieutenant signaled to Keize and Second Lieutenant Commander Teso Broosh. Broosh inquired with Heirorius about whether it was Lark who was contacting them, which Heirorius confirmed. The colonel and Lark then engaged in conversation, agreeing to a one-on-one duel while their fighter wings remained at bay. After Keize confirmed his agreement, he instructed Heirorius to terminate the comm channel.
Heirorius made an appearance in the 2021 novel titled Victory's Price, the concluding volume of the Star Wars: Alphabet Squadron trilogy penned by Alexander Freed.