Iona (SN: IOA 7201-4) is a UNSC Artificial intelligence construct employed by the Office of Naval Intelligence. Iona was originally built for ONI intelligence analysis, and had no experience with Spartans prior to Operation: BLOWBACK.
She was to assist SPARTAN-II Team Black during Operation: BLOWBACK, a covert UNSC Naval Intelligence mission to capture and destroy Covenant ships in Sub-Sector 35, on board the ONI-commissioned prospecting ship UNSC Long Time Coming. Just as the operation was about to start, the ship received a peculiar burst transmission of unknown origin. Iona asked the ship's Captain Moreland for more time to analyze the message, but Moreland cared little about the AI's pleas and ordered the ship to jump into Slipspace. Just as they did, Iona realized the message was a warning of an astrogation hazard in their way. In an instant, the ship was hit by energy bombardment from Line Installation 1-4, and dropped out of Slipspace, soon crashing on a desolate moon. After the crash, Iona assessed the damage to the ship and awakened Team Black. She scanned the moon's surface, and it was soon discovered that it lacked a breathable atmosphere, and that an immense underground complex with breathable air was located nearby. Team Black decided to head to the structure, with Iona attached to Victor-101's MJOLNIR armor.
After Black-One was captured by a Gatherer, Iona assisted Black-One and Black-Three on their efforts to rescue her. Black-One was taken into a holding cell deep in the Line Installation, for inspection by its Monitor, 686 Ebullient Prism. After a brief skirmish with Covenant forces also present on the moon, Iona managed to convince some of them to a temporary alliance, due to them having a similar problem. As Three and Four were on their way to where One was being held, Iona's secondary interface was taken over by the Monitor who was trying to hinder the team's progress. Prism, being a much more advanced construct, chased Iona through Black-Four's MJOLNIR armor systems, and was about to overpower and erase her. However, Prism became distracted when passing through a visualization of altered logs of Black-Four's training. Simultaneously in the physical world, Black-One escaped from her cell and fired at Prism with a Gatherer's energy weapon, making the monitor disappear from Iona's systems.
Meanwhile, after subtle manipulation by Prism, Black-Four became determined to settle an old personal grudge with Black-Three. The two engaged in a fight despite Iona and Three trying to settle the matter peacefully. Finally, Iona managed to convince the two to stop fighting and focus on the mission at hand. They headed to the Installation's control center, where the team, now united, destroyed Prism while bringing down a Covenant Fleet with the Installation's main weapon. After the fleet crashed to the moon, Iona analyzed the wreckage, finding a possibly functional Slipspace drive in one of the Cruisers. Before the team exited the Installation, Iona warned them of over a hundred live Covenant outside, and suggested they wait for the enemies to eventually die of asphyxiation due to the moon not having a breathable atmosphere. Despite this, the team moved outside immediately to engage the enemy forces, with Black-Three declaring the fight to be "almost fair" for the Covenant.
Over the course of the events, Iona occasionally filed status reports of the team's progress. When she was infiltrated by Prism, she already filed a message only to be sent in the event of a total mission failure, or if Team Black was to be neutralized.
As a unique feature not seen in other AI, she has a secondary, more simplistic "ghost" interface layered over her actual one. This was intended as a cover to deceive remote scanners, making her appear to them as a simpler AI, affordable by civilian miners. She is known to accidentally switch to this interface without realizing it in unexpected situations. This secondary interface also changes her avatar, to a childlike version of her default appearance.
She is also able to communicate in 306 languages.
- Iona serves as the narrator of the Halo: Blood Line comic series, occasionally commenting on the events from an outside standpoint as if they had already happened. The status reports filed by her also serve as the introduction pages to each issue. The introduction message for Issue 4 is by 686 Ebullient Prism, due to it having infiltrated Iona's systems during the events of the previous issue.