Halo Alpha
Halo Alpha

We've come to take Sigma Octanus IV back from the Covenant. To do that, we're going to kill every last one of them.
— John-117 to Corporal Harland

The Battle of Sigma Octanus IV was fought between the UNSC Defense Force and the Covenant in mid-2552.


Opening Actions[]

On July 17, 2552, Ensign William Lovell logged a large gravitational anomaly inside Slipstream space. Deciding that it could not be any form of Covenant starship based on its immense size, Lovell passed it off as an asteroid, sent his hourly report, and thought nothing more of it.[5]

However, over Sigma Octanus IV, Commander Jacob Keyes, commanding officer of the destroyer UNSC Iroquois, realized that the large mass was in fact a battle group of Covenant ships after reading a report by Fhajad-084. The Covenant ships were flying in close formation; Large masses bend slipspace more easily than in real space, creating the illusion of a single large mass when there are in fact several. Keyes concluded that the mass was comprised of four Covenant frigates. However, when the Covenant battle group exited slipspace, the Iroquois found itself outmatched by the arrival of not four frigates but one Covenant carrier, one RPV-class light destroyer,[4] and two frigates (medium-sized ships).[6]

Despite the hopeless tactical situation, Commander Keyes resolved to attack. The Iroquois set a collision course for the destroyer at emergency acceleration while launching a nuclear warhead in what seemed to be the wrong direction. The two escorting frigates proceeded to launch a salvo of plasma, but the Iroquois managed to evade by utilizing the emergency thruster. Having missed their target, the plasma came about and continued to track and home in on the UNSC warship.

The trailing plasma was to prove critical to the success of Keyes' strategy. A last minute course correction allowed the Iroquois to merely "graze" the destroyer's shields rather than smash directly into the ship properly, resulting in the destruction of a large portion of the Iroquois' armor (Keyes had torn through 2 meters of titanium and had breached every bottom deck of the Iroquois). However, the tracking plasma was unable to correct for the sudden maneuver of their target, and in consequence, impacted on the destroyer instead. A heavy salvo of Archer missiles sent the remaining Covenant Warship to its destruction.

With the momentum built up during the first phase, the Iroquois performed a slingshot maneuver around the planet. Once safely away, the nuclear warhead deployed earlier, was detonated, completely draining the shields on the two frigates. Having completed its orbit, the Iroquois resumed its attack and destroyed the two Frigates with two heavy MAC rounds and hundreds of Archer missiles.

Its escorts destroyed, the carrier then disengaged and escaped out system but not before leaving 34 dropships and a small ship to continue the ground assault.[7]

Ground battle[]

Camp Alpha - Sigma Octanus IV

Ruins of Alpha Headquarters.

With thousands of Covenant soldiers deployed on the ground, and the city of Côte d'Azur in their hands, 1600 Marines under General Kits were sent in. A small deployment of Orbital Drop Shock Troopers dropped alongside the Marine force, but did not participate separately from the marines; Devesh Bhasin died during the drop due to malfunctions in his Single Occupant Exoatmospheric Insertion Vehicle.[8]

Upon landing, the Marines set up their command center, Alpha Headquarters and a forward base, Firebase Bravo. The troopers were forced to operate with little intelligence of the surrounding area. Satellite scans were rendered useless by the fog and jungle canopy. Kits failed to realize that the jungle was crawling with Covenant, including a new race which was yet to be encountered by the UNSC; the Hunters. Lieutenant McCasky was ordered to take his platoon to observe Covenant activity in Grid 13 x 24. They traveled to the area by Warthog, but almost the entire platoon was wiped out by Hunters save for Corporal Harland, Privates Fincher, Walker and Cochran. Harland ordered a retreat as soon as he clearly saw the Hunters, but despite this Cochran was still wounded by a Needler. Although hounded by Banshees, the fireteam managed to destroy all pursuing Covenant and fall back safely. They found that Firebase Bravo had been completely overrun by Covenant forces and its survivors were systematically being hunted down and slaughtered. When they made it back to Alpha Headquarters, they found that it had also been mostly destroyed. With only fourteen enlisted men surviving on the planet's surface, Corporal Harland was forced to assume command.[9]

With the failure of the Marine strike team, the SPARTAN-IIs were sent in. Arriving at the destroyed H.Q., the squad, consisting of SPARTANs-005; 029; 058, 087; 104; 117, and six others quickly secured the base. After they arrived, Spartan 117 broke them into three four-man teams and personally assumed command of Blue Team. He sent Red and Green teams on their missions.

Côte d'Azur[]

Main article: Operation: OCEAN BREAKER

Blue Team's mission was to infiltrate and destroy Côte d'Azur, as the city was a landing zone for Covenant forces.[10] Blue Team slogged through the jungle, arriving at Côte d'Azur. Entering the storm drains, Blue Team discovered a new Covenant race, the Huragok.[11] Investigating Covenant activity in the Côte d'Azur Museum of Natural History, Blue Team discovered that the Covenant were scanning what appeared to be a simple piece of igneous rock, and sending the information to a ship in orbit. The team entered a massive firefight with two Hunters, which was a victory at the expense of James' arm, recovered the rock, and escaped.[12]

With a group of surviving civilians evacuated, the SPARTANs returned to H.Q. and detonated a HAVOK Nuclear Warhead, destroying Côte d'Azur and removing the Covenant presence on the planet.[13]

Second Space Battle[]

Space battle- Sigma Octanus IV

Admiral Stanforth's fleet engaging the covenant at Sigma Octanus IV

With the ground battle continuing, more UNSC ships arrived in orbit over Sigma Octanus IV. At 0625 hours, a fleet of Covenant vessels were detected on the edge of the system. The 48 available UNSC warships, including the Iroquois and Stanforth's flagship, the Marathon-class cruiser Leviathan, formed a tight "checkerboard" formation that allowed for them to fire all their MAC guns simultaneously at the Covenant Fleet with a single massive volley. However, this restricted the mobility of the UNSC fleet, and left them unable to evade the extremely accurate Covenant plasma torpedoes.

When the battle commenced, the Covenant Fleet took a severe beating from the UNSC's opening MAC salvo, but promptly returned fire with a salvo of plasma torpedoes. The repair station UNSC Cradle moved in front of the fleet's formation, acting as a sacrificial shield. The station's mass absorbed the Covenant Fleet's first salvo, at the cost of the installation and its entire crew. This allowed the vulnerable UNSC ships to dedicate all power from engines to their MAC guns and immediately fire a second salvo. Only eight Covenant vessels remained active after the initial barrage, including several cruisers and destroyers. The UNSC fleet then scattered and proceeded to engage the Covenant Fleet, which responded by releasing its Seraph fighters and closing to engage in ship-to-ship duels. The Iroquois spotted a Covenant stealth ship in orbit above the planet and attempted to destroy it with a barrage of Archer missiles, but the attack was foiled when the stealth ship jammed the missile guidance locks. In response, Iroquois simply rammed the much smaller ship, stopping the Covenant from transmitting data from the planet's surface. The remaining Covenant vessels soon fled the system.[14]


The battle was one of the few major victories that the UNSC had won in space since the Battle of Psi Serpentis. Despite the loss of many ships, Admiral Stanforth had planned this battle to be a much needed victory and morale boost for all of humanity.[15] It introduced the tactic of using a refit station to protect UNSC ships. The Covenant however had achieved their goal of data retrieval from the Forerunner crystal broadcast, which revealed to them the location of Installation 04. After the battle had ended the UNSC Iroquois had a tracking probe attached to it masquerading as debris from the battle. This led to the catastrophic discovery of Reach by Covenant forces.[16]

It later transpired that the Covenant had learned the location of one of the Halos from the transmission, which they planned to activate to begin the Great Journey.

As a result of the battle, there was much debris left in orbit around Sigma Octanus IV. HAZMAT teams swept the area but the area around the planet remained a navigational hazard for the next decade.[17] Many cities beyond Cote d'Azur were destroyed, including Caracas, Huiren, Silma and Enfield.[18]


July 17, 2552[]

  • 0000 Hours: Ensign William Lovell, aboard the UNSC Remote Scanning Outpost Archimedes, reports to Sigma Octanus IV concerning a large silhouette in Slipspace heading for the system. It is suspected to be a group of Covenant ships but it could also be an asteroid.
  • 0300 Hours: The UNSC Iroquois arrives in system on patrol. The vessel's Commanding Officer, Captain Jacob Keyes, receives the sensor information and realizes it is a Covenant threat. He contacts FLEETCOM and informs them of the situation.
  • 0320 Hours: 4 Covenant ships consisting of 1 carrier, 1 destroyer and 2 frigates arrive in the system. The UNSC Iroquois engages the enemy and requests reinforcements. The UNSC Gettysburg and UNSC Alliance respond and begin heading for Sigma Octanus.
  • 0330 Hours: The Iroquois destroys all Covenant vessels save for the carrier using a maneuver later known as the Keyes Loop. The carrier launches landing craft toward Sigma Octanus IV, then retreats into slipspace.
  • 0345 Hours: Covenant ground forces invade the city of Côte d'Azur on the planet.
  • 0500 Hours: 47 additional UNSC vessels arrive in the system. Admiral Michael Stanforth, aboard the UNSC Leviathan, takes command.
  • 0520 Hours: Reinforcements of 400 marines, led by General Kits, begin landing around Côte d'Azur
  • 0600 Hours: Covenant forces ambush and obliterate all marine forces on the ground. Only 14 enlisted men survive. Corporal Harland assumes tactical command.
  • 0625 Hours: Covenant vessels begin appearing on the far edge of the system.
  • 0650 Hours: SPARTAN-IIs arrive on the surface to reinforce surviving marines.
  • 0900 Hours: Spartans assume tactical command on the ground.
  • 1800 Hours: Spartans and marines begin a counterattack on Côte d'Azur.
  • 2010 Hours: Spartans arm nuclear device below Côte d'Azur.
  • 2039 Hours: Nuclear warhead destroys all Covenant ground forces at Côte d'Azur.
  • 2120 Hours: General quarters is sounded aboard ships and the opposing Fleets close to engage.
  • 2130 Hours: Repair station UNSC Cradle moves to protect UNSC Fleet. First salvos are fired by Covenant vessels.

July 18, 2552[]

  • 0500 Hours: All Covenant vessels either retreat or are destroyed. Battle concludes.



Naval Assets[]

Class Name Status
Marathon-class heavy cruiser UNSC Leviathan Survived
Halberd-class destroyer UNSC Iroquois Survived
Unknown UNSC Lancelot Unknown
Unknown UNSC Gettysburg Survived
UNSC Allegiance Unknown
UNSC Fair Weather Destroyed
Refit Station UNSC Cradle Destroyed
Remote Scanning Outpost Archimedes Unknown

Military Personnel[]

Branch Rank Name Status
UNSC Navy Vice Admiral Michael Stanforth Survived
Captain Jacob Keyes Survived
Lieutenant Dominique Survived
Hall Survived
Aki Hikowa Survived
Jaggers Survived
Ensign William Lovell Survived
Master Chief Petty Officer John-117 Survived
Petty Officer First Class Frederic-104 Survived
Petty Officer Second Class James-005 WIA
Li-008 Survived
Joshua-029 Survived
Vinh-030 Survived
Isaac-039 Survived
William-043 Survived
Anton-044 Survived
Linda-058 Survived
Malcolm-059 Survived
Kelly-087 Survived
UNSC Marine Corps General Kits KIA
Second Lieutenant McCasky KIA
Corporal Harland Survived
Private Fincher Unknown
Walker Survived
Cochran Unknown
Unknown Devesh Bhasin KIA



  • There is an apparent time discrepancy in the continuity of Halo: The Fall of Reach as pertaining to the exact times of the chapters. Chapter 19 begins at 0600 hours while Chapter 20 begins at 1800, and it seems as though there is no significant lapse of time between them. Chapter 22 Begins at 2010 Hours and then Chapter 23 begins at 0500 hours, yet they all claim to have happened on July 17. This may have been a typo, with Chapter 23 meant to be on July 18 or a flashback of sorts. It is likely that Chapter 19 begins much later than 0600, since the marines were only deployed at 0600, and even if the bases were set up instantly, they still took 'a couple hours' to get from the firebase to grid 13x24.
  • Page 156 of Halo: The Fall of Reach states that the repair and refit station UNSC Cradle was over a square kilometer and that three destroyers could be eclipsed by its shadow. Exactly how it could cover the entire UNSC fleet present is not made clear. The UNSC ships may have positioned themselves behind the Cradle in a specific formation for maximum protection. It is also possible that repair and refit stations are larger than stated.
  • The dates given for the last three sections of the book are incorrect. The novel states that they occurred in 2542, however, this has been confirmed to be a typo in the book. The actual events occur in 2552; the penultimate year of the Human-Covenant war. There are other, more minor, date errors in the book, some which corroborate the 2542 timeline, and fewer which corroborate the 2552 timeline.




  1. The ships fired a salvo of 63 MAC rounds (Halo: The Fall Of Reach, page 193), thus 15 ships must've had 2 MAC guns. With one Marathon-class cruiser, that leaves 14 destroyers.
  2. 48 -14 -2 -1 = 31
  3. Halo: The Fall of Reach, page 155
  4. 4.0 4.1 Halo: The Essential Visual Guide, page 48
  5. Halo: The Fall of Reach - 2010 Edition - Chapter 15
  6. Halo: The Fall of Reach - 2010 Edition - Chapter 16
  7. Halo: The Fall of Reach - 2010 Edition - Chapter 17
  8. Xbox.com: - In the "search terms" under "D." (Defunct)
  9. Halo: The Fall of Reach - 2010 Edition - page 199
  10. Halo 5: Guardians - Bonus Item: John-117 Dossier Card
  11. Halo: The Fall of Reach - 2010 Edition - Chapter 20
  12. Halo: The Fall of Reach - 2010 Edition - pages 240 - 243
  13. Halo: The Fall of Reach - 2010 Edition - Chapter 22
  14. Halo: The Fall of Reach - 2010 Edition - Chapter 21
  15. Halo: The Fall of Reach, page 160
  16. Halo: The Fall of Reach - 2010 Edition - Chapter 23
  17. Halo: The Fall of Reach
  18. Halo Waypoint: Data Drop 2