Massacre of the Outer Colonies

The Outer Colony Massacres were a series of engagements during the early portion of the Human-Covenant war.

The Insurrection
Prior to the appearance of the Covenant, the UNSC and CMA were knee deep in brush wars with angry colonists. This had inadvertently helped give the UNSC and CMA new naval tactics, which would prove to be useful during battles with the Covenant.

Prelude at Harvest
Thinking the planet had been constantly ransacked by Insurrectionists, the Office of Naval Intelligence sent Jilan al-Cygni to investigate the planet. The Covenant would then fall for a trap that Jilan and two UNSC trainers would set up. This confirmed that it was not Insurrectionists, but rather aliens. The three decided that they needed to prepare for a first contact scenario.

Opening at Harvest
The disastrous first contact broke down into a heavily one sided battle. Local militia and UNSC training forces managed to mount an admirable defense and saved many civilians. Ultimately, the planet was glassed by a single Covenant vessel.

A scout ship, the CMA Argo was sent to investigate the planet. When the CMA lost contact with the Argo, Battlegroup 4 was assembled and sent to Harvest. Out of three ships in the group, one managed to limp its way back to Reach to tell of what was encountered.

Early Losses
On November 1, 2525, the UNSC went to full alert and stripped the CMA of its forces, giving them to NAVCOM and UNICOM. On the 27th of the same month, Chi Ceti IV was assaulted by a Covenant ship at the same time SPARTAN-II forces were receiving their MJOLNIR Powered Assault Armor. That same year saw the loss of Biko, and the beginning of 2526 saw the destruction of Bliss.

Cole Fights Back
The UNSC had Preston Cole lead a battlegroup to retake Harvest. He would win this battle, but a protracted military campaign would begin on the planet. The Covenant had already pushed on to Green Hills and Second Base. Following the first victory at Harvest, Circinius IV was assaulted. This resulted in the loss of one of UNSC's top military schools, the Corbulo Academy of Military Science. After that, Madrigal was lost.

Preston Cole continued to lead UNSC forces out in the Outer Colonies. He managed to score a more victories in the Battles of Alpha Aurigae and XI Boötis A. The Covenant still managed to attack Hat Yai, despite these UNSC victories.

Continuing Losses
By January 1, 2530 the casualties in the Outer Colonies had amassed to a total of 62,154,022 deaths. The UNSC would suffer another loss with the attack on Eridanus II. Though Preston Cole would score another victory at Groombridge 1830 system during the Battle of the Great Bear. This victory would lead Cole to create the "Cole Protocol" after interrogating a prisoner of the battle.

Arcadia was also attacked but not glassed, leaving the planet mostly to nature. Arcadia would be the last known battle the famed would participate in before officially being listed as "Missing in Action". Vodin was lost in 2532, and Jericho VII was lost along with Charybdis IX before the Covenant breached the Inner colonies. Refugees from the Outer Colonies also had begun fleeing to the Outer Fringes trying to escape the Covenant's wrath.

Aftermath
After the Covenant destroyed a majority of the Outer Colonies, they began to press inwards on the UNSC, taking out the Inner Colonies. As well, some Outer Colonies would fall after these massacres, such as Meridian.

Some Outer Colonies managed to escape the Covenant altogether. Though with the retreat of the UEG and UNSC saw these planets face famine, plagues and social collapse. In some cases, these planets had local ecology just take over what was left on these planets.

2525

 * The First Battle of Harvest takes place.
 * The UNSC strips down the CMA of their resources and divides it among NAVCOM and UNICOM.
 * The Battle of Chi Ceti takes place.
 * The Battle of Biko takes place.

2526

 * The Battle of Bliss takes place.
 * The Second Battle of Harvest takes place. Following which, the Harvest Campaign begins.
 * The Battle of Circinius IV takes place.
 * The Battle of Alpha Aurigae takes place.

2528

 * The Battle of Alpha Aurigae takes place.
 * Madrigal is destroyed.

2530

 * At this point, there have been a total of 62,154,022 deaths in the Outer Colonies.
 * The Battle of Eridanus II takes place.
 * The Battle of the Great Bear takes place.

2531

 * The Harvest Campaign comes to a conclusion.
 * The Battle of Arcadia takes place.

2532

 * The Battle of Vodin takes place.

2535

 * The Battle of Jericho VII takes place.
 * The Battle of Charybdis IX takes place.