Mayday! Mayday! We are under attack by a ship of some kind! We can't stop it! It's...
—The captain of an Imperial Victory-class star destroyer before being destroyed by the Iron Harbinger
It had devastating firepower surpassing most Imperial ships, as well as nearly impregnable shields, and was one of the most dangerous ships in the galaxy.
8311 wanted to lead Legion fleet activities himself, so he ordered a specially modified flagship for himself. Mandal Hypernautics was commissioned for this task, and 8311 paid them handsomely to give him a heavily upgraded capital ship. A month after it was commissioned, the Harbinger rolled out of Mandal Hypernautic's shipyards aboveMandalore, built to 8311's specifications. It was equipped with extra weaponry and shielding, making it capable of taking on even an Imperial I-class star destroyer.
Sophisticated automated systems were installed on the ship to take care of the more tedious tasks, but it still retained a large crew to defend against boardings.
At one point during the Legion's reign, the Harbinger was installed with an Impervious Device, capable of rendering it invincible. However, the device used a lot of power, and 8311 only used it in emergencies.
The Harbinger's first operation was when a Steel Legion fleet attacked an Imperial storage station above Anaxes. 8311 himself led the attack from Harbinger. The station was guarded by three Victory-class star destroyer and one Imperial class. Within minutes, concentrated fire from the Harbinger reduced the Victories to scrap, and the rest of the Legion fleet dealt with the remaining star destroyer, which was disarmed by fire from the Harbinger. Legion boarding crews were now free to board the station, and stole vast amounts of credits and resources.
The Harbinger's next notable mission was when the Legion was challenged by some rebels near Bespin, who were preying on Imperial supply lines, which the Legion was also raiding. The rebels openly attacked Legion pirate vessels in the area, which led to 8311 tracking their base of operations to a nearby asteroid field. A small Legion flotilla, led by the Harbinger, located the rebel base and utterly destroyed it, as well as the rebel space forces there, which had a Mon Cal cruiser amongst themselves. The Legion was now free to reap the Imperial supply ships.
Shortly after that, after a series of arduous missions, the Legion gained the Impervious Device, and 8311 installed it on the Harbinger, further increasing its prowess.
However, the next major mission for the Harbinger was considerably more dangerous. An Imperial Moff named Deras decided to openly go to war with the Legion after his fleet was humiliated by a Legion raid, and 8311 realized that this was considerably more dangerous then previous threats. To try and stop this conflict from developing, 8311 launched a lightning raid on the Moff's fleet, which was assembling near Felucia. A fierce battle ensured, and the Harbinger went head-to-head with the personal flagship of the Moff, suffering considerable damage. Regardless, the battle was a Legion victory, and stymied the Moff's plans.
8311 quickly established a secret dock in an asteroid field near a Black hole for the Harbinger only, where it underwent repairs. Meanwhile, the Moff struck at a Legion battle platform, and overpowered the Legion fleet there, destroying the platform. Quickly, 8311 reluctantly rushed repairs to the Harbinger, and once again began engaging the Moff's fleet. After a series of battles, the Legion was finally triumphant, but the Harbinger was critically damaged, so it underwent automated repairs at the dock.
After the Empire tried to destroy 8311 at his home on Nar Shadda and the Legion temporarily collapsed, the automated repairs to the Harbinger carried on, until it was completely fixed. The computer at the dock, programmed by 8311 himself, decided to add a hangar to the Harbinger as well as extra weaponry.
Around the Battle of Endor, when 8311 began to rise to power again and the Legion began rebuilding, 8311 returned to the dock where the Harbinger still remained. Impressed by the upgrades the computer had given it, he continued to use the ship as his personal flagship, even when he began to lose interest in the Legion and focus more on his private droid army on Hypori. The Harbinger served in the Yuuzhan Vong War as 8311 fought alongside the New Republic and later the GFFA, suffering damage along the way. Despite constant upgrades and modifications, the Harbinger was beginning to show its age, and 8311, despite his sentimental attachment to the ship, realized it. By the end of the war, the Harbinger was in bad shape.
Soon, around the Dark Nest Crisis, when 8311 went into a brief conflict with Jack Nebulax, and again used the Harbinger to lead his fleets. At the last battle of the brief conflict, after which both sides concurrently sued for peace, the Harbinger took very heavy damage to its vital systems, and part of it fell away. Realizing that the Harbinger had had her day, 8311 decommissioned her and sold her to a starship museum. She was succeeded by the Iron Harbinger II, an Iron Glory-class destroyer.
- Forces of Corruption: The Empire's Beginning