Battle of Nysa

Previous:	Battle of Suban
Concurrent:	Battle for Zeta Halo
Battle of Nysa
Date:	February 29 - March 4, 2560
Location:	Nysa, Hyades system
Outcome:	Banished victory
Details Belligerents UNSC Spartan Operations UNSC Marine Corps UNSC Navy (late in battle) Swords of Sanghelios (late in battle) Banished New Colonial Alliance Commanders Chief of Staff of Spartan Operations Jun-A266 (late in battle) Spartan Commander Laurette Agryna Chief Engineer Hannah Roberts† Shipmistress Vedu 'Ehtar (late in battle) Bloodstar Ilsa Zane Chieftain Atticus Strength Johnson Academy garrison Over 50 Spartans Over 100 Marines and other personnel Eleven Pelicans Four Condors One Zheng He-class courier Reinforcement One Mulsanne-class light frigate UNSC Fearful Symmetry One A'uzr-pattern sword frigate Sword of Conjunction Three Riftborn teams Amity Wing Harmony Wing Sympathy Wing Two Spartan-IIIs AI Iratus New Colonial Alliance One Banished dreadnought Ghost of Kholo Several Eklon'Dal Workshop Phantoms Several Kaelum Workshop Banshees Several Qavardu Workshop Gravemakers Several Qavardu Workshop war-skiffs 1 Spartan-IV Several Jiralhanae Several Humans Several Kig-Yar Several Unggoy Casualties Several Marines and other personnel Hannah Roberts Several Spartans Sinclair Four Condors One Zheng He-class courier One Riftborn operative Several Jiralhanae Several Kig-Yar Several Unggoy

The Battle of Nysa was a military conflict between the United Nations Space Command and the Banished for control of Nysa; a frontier world in the Hyades system used by the UNSC as a hidden fallback point during their war against the Created. The battle itself was predominantly centred on the Avery J. Johnson Academy of Military Science on the planet's surface, thanks to a Banished smart AI, Iratus, managing to break containment and infect the facilitiy's wider networks on February 29, 2560. Iratus was able to disable the academy's defences and alert the Banished to Nysa's location, resulting in a large invasion force of the Banished-aligned New Colonial Alliance beginning their attack on the world on March 3.

During Iratus' initial outbreak in late February, Academy personnel were able to send out an SOS message of their own, which was picked up by UNSC-Swords of Sanghelios forces aboard Anvil Station. On March 4, a UNSC-Swords task force was able to enter the system and evacuate key staff from the Avery Johnson Academy, unable to match the tonnage of the Banished invasion in a conventional fight. As such, Nysa was left to fall to Banished occupation, with the NCA's leader, Spartan Ilsa Zane, able to retrieve Iratus for herself.

Background

The Avery J. Johnson Academy's interstellar communications facilities.

The frontier world of Nysa was established in the early years of the Human-Covenant War by the United Nations Space Command as a secretive, hidden fallback point to use as a base for the military to operate from. The world was originally the site of several Office of Naval Intelligence Section Three research sites (such as Site Z), though some were eventually shuttered and used as a basis to form new military installations. One of the most prominent of these was the Avery J. Johnson Academy of Military Science, built atop an older ONI facility in the Hesychius Mountains and used for the training of new SPARTAN-IVs; with the outbreak of hostilities with the AI cabal known as the Created, the UNSC accelerated Spartan recruitment efforts. The world was used as a base from which the UNSC could strike at targets at their choosing, with a notable example including its use as a base for the super-heavy cruiser UNSC Victory of Samothrace to operate from during its mission to Rossbach's World in early November 2559. Due to the world's secretive nature, it had relatively few defenses save for its ground teams (notably the Spartans of the academy), which were reduced even further in mid-December 2559 when slipspace-capable spacecraft were recalled to Earth to bolster the UNSC Home Fleet in advance of a massive attack on the planet by the Banished.

After the defeat of Cortana and the Created at Installation 07 on December 12, 2559, Nysa continued to recruit and train new Spartan recruits, bringing a new cadre including Spartan "Rook" into the base on December 20. At this time the base also began to deploy its Spartans in operations against the Banished; on January 24, 2560, the academy's commanding officer Spartan Commander Laurette Agryna deployed two Spartans, Sigrid Eklund and Hieu Dinh, on a reconnaissance mission to the Chiltift Basin shipbreaking yards on Camber. The ex-UNSC shipbreaking facility had become the site of a Banished salvaging operation, the target of the two Spartans' reconnaissance efforts. While deployed on Camber, the two came across a unique smart AI developed from a Jiralhanae brain, Iratus, which proceeded to infect Dinh's neural interface and render the Spartan comatose. Eklund proceeded to commandeer a Banished Phantom dropship and use it to transport Dinh back to the academy on Nysa for medical aid, arriving on February 15.

In an effort to pull Iratus out of Dinh's neural interface, Agryna uploaded a simulation of the Banished facility on Camber into the Academy's combat simulator, and assigned Spartans to participate in the simulation to act as bait, and trap Iratus into an ONI server. The plan was a success, and Iratus was trapped, saving Dinh's life. Dinh awoke from his coma on February 20. Over the ensuing week the academy's technicians began to notice strange glitches happening throughout their system, though at the time the full scope of the threat Iratus posed was simply dismissed as "a caged creature rattling its bars"; unbeknownst to the UNSC, the AI had managed to escape its confinement in the academy's servers and break into the ONI databases underneath the academy. On February 29, Spartans Dinh and Rook ventured into the ONI facilities underneath the academy to find that Iratus had successfully broken containment and was now in the process of downloading all of the classified intelligence kept there - particularly that concerning the Spartan programs. After being discovered, Iratus disabled the academy's short-ranged communications, beginning hostilities.

Battle

Iratus' control

Iratus began his attack on the academy by disabling the base's short-ranged communications, which threw any initial effort to respond to the breach into disarray. For the AI, he knew that the base's large Spartan complement would make a Banished relief force hesitant to attack the facility; as such, he focused on downloading and processing large quantities of ONI classified information - reasoning that if he made himself more valuable, the Banished would be more willing to pay the price in casualties to conduct the attack. While Iratus' end goal was ultimately taking control of the base's communications equipment to broadcast a message to the Banished, the academy's technicians responded by flooding the network with zetabytes of randomly-generated junk data for the AI to sift through. However, this was only a temporary measure intended to slow the AI rather than stop him. While Spartan Dinh returned to the academy's AI lab to inform Commander Agryna of the threat, Spartan Rook assembled teams to head to the academy's outlying outposts to similarly-inform them. Due to the academy's construction atop an older and unmapped ONI facility, no one knew if the ONI tunnel network connected to the rest of the facilities on Nysa and, if so, also put them at risk of Iratus' control.

As such, Commander Agryna reasoned that the most likely step for Iratus to take was to call in a Banished armada to assault the planet - something the world was ill-equipped to deal with. Instead, an evacuation of key assets and personnel was the only realistic solution, using the base's four Condor dropships and lone Zheng He-class courier - the other ships on the world having largely redeployed during the battle of Earth the previous December. Spartan Eklund volunteered to organise the evacuation alongside Spartans Page and Ionescu. Meanwhile, Agryna moved to enact the Cole Protocol to deny as much to Iratus as possible, though with communications down and the facilities spread apart, it was an infeasible action to take, with the commander unwilling to repeat the destruction of Laconia Station some months prior. Instead, she and Dinh headed to the base's slipspace COM launcher - originally installed for secure communications that could not be intercepted by the Created - where they prepared an SOS message to be sent to Anvil Station. With Laconia destroyed and its sister-stations Naxos and Virgo potentially compromised, Anvil remained the only safe option, even despite the commander's reservations about working with Sangheili.

Marines survivors of the missile attack attempting to rescue the wounded.

While the UNSC call for help was successfully sent, Iratus was also able to take control of the base's interstellar communications equipment, making his location known to the Banished and inviting them to attack. He also took over control of the academy's five surface-to-air missile launchers, using them to shoot down the evacuation courier as it lifted into orbit. Iratus then threatened to use the launchers to target the academy itself, presenting Agryna with a dilemma - she could let the base be destroyed and leave the anti-aircraft weapons online, or she could order their destruction and leave the base defenceless when the main attack came. She ultimately chose the latter, and ordered the deployment of all available aircraft on-site to destroy the launchers while their automated systems reloaded. Ten D77 Pelicans were used for this air strike while the eleventh was used to conduct a search-and-rescue for survivors of the failed evacuation and ferry them back to the base, where they would stand their ground.

Invasion

Three Spartans rush to defend the academy.

At 1139 on March 3, 2560, Iratus' signal was answered by the Banished-aligned New Colonial Alliance, who entered Nyssan orbit in their dreadnought Ghost of Kholo. The NCA spent the first few hours in orbit scouting the world and mapping out its key facilities, assessing it for attack. During this time, Chieftain Atticus advised their leader Ilsa Zane on how to maximise the NCA's gain from the invasion in climbing the ranks within the Banished. Eventually, Ilsa Zane invited the UNSC commanders on the planet to a parley conducted at 1532 hours in the Hesychius Mountains; Zane offered Agryna the chance to surrender Iratus to the Banished without a fight, and in return she would leave with bloodshed. Upon seeing Spartan Dinh as part of Agryna's party, she further offered to keep her word on that deal, if Agryna allowed her to take Dinh with her so that she could settle her own unfinished business with him. Agryna refused the offer to Zane's delight, resulting in the Banished beginning their invasion of Nysa, deploying drop pod troops in advance of a wave of drop bases and occupation infrastructure onto the planet.

Over the next few hours, Banished troops flooded the academy with numbers far too great for the defending forces to meaningfully hold off. As such, the academy's Spartans were slowly pushed further and further back into the base. By 1849 on March 3, Spartans Agryna and Eusebio were hold up in the main campus fighting off oncoming Jiralhanae and Kig-Yar supported by Kaelum Workshop Banshee flyers. Spartan Eklund fell back to a relay junction inside the base, prompting Agryna to order Spartans Dinh, O'Brien, and Sinclair to go and relieve her while herself, Eusibo, and Denning held their ground. Once they reached Eklund, O'Brien was engaged and pinned to a wall by a Jiralhanae Berserker, prompting Sinclair to jump on its back and stab it with a combat knife. The Brute responded by throwing Sinclair into a nearby wall and beating him to death, before being put down by Dinh's CQS48 Bulldog shotgun. At this point, the surviving three Spartans retreated inside the base and were ordered by Agryna to begin enacting the Cole Protocol across the academy's facilities. Agryna also attempted to institute a lockdown of the base to buy time, though the lockdown was almost immediately reversed, and all of the base's doors and gates opened, by Iratus. One of the Spartan teams responsible for instituting the Cole Protocol was led by Spartan Rook, who successfully fought through the Banished to achieve their goal.

Relief and evacuation

Agryna's SOS from February 29 was ultimately recieved by Anvil Station at around 2100 on March 3, 2560 - around nine hours after the start of the invasion of Nysa. As such, the station's commander Stationmaster Toda 'Murajai was unable to assemble more than a hasty task force to go and respond to the distress signal. The task force departed two hours later, and consisted of a single A'uzr-pattern sword frigate operated by the Swords of Sanghelios; Sword of Conjunction. The frigate was staffed with multiple wings of strikecraft alongside several teams of Riftborn special forces operatives: both joint UNSC-Swords units consisting of Spartan and Sangheili personnel designed to foster cooperation among the two allies. Sword of Conjunction was joined by a UNSC Mulsanne-class light frigate, UNSC Fearful Symmetry for the operation.

Sword of Conjunction emerged from slipspace in the Hyades system at 0327 on March 4; by this time the fighting on Nysa's surface had been raging for around fifteen hours, and Fearful Symmetry was stationed at the outer edge of the system. The sword frigate began to assess the situation by deploying scout-eyes onto the planet below and, once satisfied, Conjunction signalled Fearful Symmetry that the two should head toward Nysa. While the two sub-capital ships were outmatched by the NCA's dreadnought, they were able to distract it long enough to conduct an evacuation. Sword of Conjunction deployed its strikecraft wings Amity, Harmony, and Sympathy, into the fray, with the Banshees intended to draw off enough attention to allow for a quick exfiltration. With intelligence provided by the scout-eyes, Conjunction then conducted a pass of the academy and at 0337 dropped six Yado-pattern stealth drop pods containing the frigate's Riftborn warriors into the base. The Riftborn were given a simple task: find Commander Agryna and, if possible, any other survivors to evacuate.

The Riftborn were deployed in pairs each consisting of a single Sangheili and Spartan, though it was ultimately Ovi 'Taar and Adrian Vesco who ended up finding the commander first. The two were drawn to the base's firing range and armoury by the ping of several friendly IFF tags in that direction, though stumbled into the armoury to find a Jiralhanae Chieftain handing out scavenged Bulldog shotguns and SRS99-S7 AM sniper rifles to his adjutant Jiralhanae and Kig-Yar troops. The two engaged the group and were largely successful in dealing with them, though Ovi 'Taar was ultimately killed by the chieftain and Vesco left heavily injured.

Jun-A266 during the battle.

Agryna, Dinh, and Eklund ultimately stumbled upon Vesco and brought him to the AI lab at 0429 to hold out alongside several Marines and base staff including Chief Engineer Hannah Roberts. By this time, the enactment of the Cole Protocol and RUINA subroutines across the base forced Iratus back into the AI lab's servers, effectively trapping him there - though he was quick to note that the Banished would break in in short order and retrieve him regardless. Commander Agryna initially insisted on staying; throughout the battle she had continuously pondered how much she could have done differently to prevent the current events, and ultimately decided that if the base was going to go down, it was only approrpriate that she go down with it. However, she was dissuaded of this notion after Vesco informed the group that he had an emergency beacon that could be used by Fearful Symmetry to lock onto their position and deploy an extraction dropship. With the option available, it was technician Roberts who ultimately persuaded Agryna and the Spartans to leave, believing that she could stay and delete as much critical data from the system as possible, and buy time for the Spartans to evacuate. Other personnel, such as Spartan Rook and those with them, were also able to escape Nysa via Pelican at the base's landing pads.

Ilsa Zane recovers Iratus' chip.

After Vesco's beacon was activated, Fearful Symmetry deployed a D77 Pelican, Bravo 198, to deploy into the academy and extract the survivors, which came in for landing around 0441 hours. The Pelican carried two SPARTAN-IIIs, Jun-A266 (the Chief of Staff of Spartan Operations) and Warrant Officer Rosenda-A344. To get into Nyssan airspace safely, Fearful Symmetry coordinated with the Pelican to do a close flyby of the academy, distracting the NCA dreadnought on station above. The frigate closed on the dreadnought's starboard side and fired at it with its Brightlance reflex laser, temporarily disabling the dreadnought while exfiltration was underway. After landing, Rosenda was able to damage a Banished Banshee with her Hydra missile launcher, securing a final killshot for Jun's sniper rifle. The two then proceeded to escort Agryna, Dinh, Eklund, and Vesco into the Pelican, which launched back into orbit to dock with Fearful Symmetry and retreat back to Anvil Station.

While Bravo 198 conducted its extraction, a squad of Marines made a final stand against the Banished assault on the AI lab, which was led personally by Ilsa Zane and Captain Praedus. The Marines were unable to hold out long, and the Banished made their way into the lab. Zane ordered Roberts to hand over Iratus' data crystal chip, who complied after some brief questioning. Despite her assistance, Zane ordered Roberts' execution and then took Iratus for herself, uploading him into her MJOLNIR Powered Assault Armor and inviting him to make himself at home. At this point, the academy (and presumably Nysa as a whole) were declared compromised, and totally lost.

Aftermath

Following her evacuation from the planet, Commander Agryna would file an after-action report to COSSPAR Jun-A266 on the events that led up to the battle and their timeline. In the report, Agryna expressed her own regret for the decisions she made that led up to the attack, and considered herself responsible for them and the losses inflicted by the Banished.

Timeline

February 29

• 1949 hours: Iratus is discovered to have escaped confinement underneath the academy, and shuts off academy communications.
• 2001 hours: Commander Agryna orders an evacuation of the base, and decides to send out an SOS to Anvil Station.
• 2008 hours: Iratus breaks through the academy firewalls, obtaining classified ONI intelligence and taking control of the base's systems in totality.
• 2038 hours: Commander Agryna and Spartan Dinh send out an SOS to Anvil Station; Iratus uses the base's communications to signal the Banished to attack.
• 2042 hours: Iratus uses the base's own missile defences to shoot down the evacuating Zheng He-class courier ship.
• 2049 hours: Agryna makes the choice to order the missile batteries' destruction, leaving the base defenceless.

March 3

• 1139 hours: The NCA's dreadnought Ghost of Kholo arrives in orbit over Nysa, beginning the Banished invasion.
• 1532 hours: The UNSC and NCA meet in the Hesychius Mountains to parley, though the UNSC refuse to surrender to the Banished. Ilsa Zane orders the invasion to commence.
• 1849 hours: Banished troops pour into the Avery Johnson Academy as Iratus lifts the base's lockdown.
• 2100 hours: Anvil Station recieves the distress call from Nysa and scrambles a response force.
• 2300 hours: Sword of Conjunction departs from Anvil Station to relieve Nysa.

March 4

• 0327 hours: Sword of Conjunction arrives in the Hyades system and begins conducting observation of the ongoing invasion.
• 0337 hours: Sword of Conjunction drops Riftborn teams onto Nysa in drop pods. Ovi 'Taar is killed by a Brute Chieftain, and Adrian Vesco is heavily injured.
• 0429 hours: Spartans Agryna, Dinh, Eklund, and Vesco hole up in the academy's AI lab alongside several Marines and technicians. Spartan Rook is successful in enacting the Cole Protocol at the base's outlying sites, which forces Iratus back into the AI lab's secure servers. Agryna and the Spartans are persuaded to evacuate the base, while the remaining technicians work to destroy as much data as possible.
• 0441 hours: Pelican Bravo 198 lands at the Academy; Jun-A266 and Rosenda A-344 escort the evacuating Spartans to safety.
• 0448 hours: Marine forces around the AI lab are killed in a last-stand.
• 0500 hours: Ilsa Zane retrieves Iratus; the Avery Johnson academy is deemed lost.

Participants

UNSC Starships Fleet Class Name Status Unknown Mulsanne-class light frigate UNSC Fearful Symmetry Active Military personnel Branch Rank Name Status Spartan Operations Chief of Staff of Spartan Operations Jun-A266 Active Spartan Commander Laurette Agryna Active Spartan Hieu Dinh Active Sigrid Eklund Active "Rook" Unknown Eusebio Unknown Denning Unknown O'Brien Unknown Sinclair KIA Ionescu Unknown Page Unknown Spartan/Riftborn operatives Adrian Vesco Active Babych Unknown Prentis Unknown UNSC Marine Corps Corporal Agnes Neely KIA Private Patton KIA UNSC Cybersecurity & Network Infrastructure Chief Engineer Hannah Roberts KIA UNSC Navy Lieutenant Mercer Active Warrant officer Rosenda-A344 Active Ensign Sethu Active Vehicles Class Name Status D77 Pelican Bravo-198 Active Swords of Sanghelios Starships Class Name Status A'uzr-pattern sword frigate Sword of Conjunction Active Military personnel Rank Name Status Shipmistress Vedu 'Ehtar Active Riftborn operatives Ovi 'Taar KIA 'Ookol Unknown 'Toizari Unknown Units Amity Wing Harmony Wing Sympathy Wing

Banished Starships Class Name Status Banished dreadnought Ghost of Kholo Active Military personnel Rank Name Status Bloodstars Ilsa Zane Active Chieftain Atticus Active Captain Praedus Active Artificial intelligence Iratus Active

Production notes

The battle for the academy reflected in Commander Agryna's visor, in the Last Stand keyart.

The Battle of Nysa, and the fall of the Avery Johnson Academy, were the subject of Halo Infinite's Operation Last Stand multiplayer event in mid-2025. The update included a Firefight playlist themed around the battle, Firefight: Battle of the Academy, which depicts the player's multiplayer Spartan fighting off Banished forces throughout the base. The update, and the playlist, are also the subject of the simultaneously-released Halo Waypoint Chronicles Halo: Battle for the Academy - Part 1 and Part 2, which tell the story as a continuation of Halo Infinites multiplayer narrative established between 2021 and 2023.

Gallery

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  A dual-spread of both Battle for the Academy covers, depicting stylised takes on both the UNSC and Banished combatants in the attack.

List of appearances

• Halo: Anvil Accord (Indirect mention)
• Halo Infinite
  • Last Stand (First appearance)
• Halo: Battle for the Academy - Part 1
• Halo: Battle for the Academy - Part 2