Onyx Conflict

Introduction
The Battle of Onyx was a heavy, prolonged military engagement between the Forerunner Sentinels, United Nations Space Command, and the Covenant.

Sentinel Activation
When Delta Halo's firing sequence was interrupted, it emitted a signal that placed all other Forerunner installations in standby mode, including the Sentinels guarding the Shield World 'disguised' as the 'planet' of Onyx. On October 31, 2552, the first of these Sentinels to awaken suddenly began attacking UNSC forces on or near Onyx. Coincidentally, Gamma Company was participating in the Top Honors exercise at the time.

Almost immediately, Team Gladius and the orbiting were destroyed and Team Katana captured. Team Saber regrouped with Kurt-051, Tom-B292, Lucy-B091, and Chief Mendez, although they had no means of summoning reinforcements from the rest of the UNSC.

Dr. Halsey, Kelly-087, and AI Jerrod arrived aboard Beatrice. Attacking Sentinels forced the ship to crash land on the planet, although all three passengers survived to link up with Kurt-051's group. Halsey proceeded to convince the resident ONI AI, Endless Summer, to send a distress message to the UNSC using the Slipspace COM Launcher. In the signal Halsey requested the deployment of SPARTAN-II's to Onyx. The launcher was destroyed shortly after firing.

The message succeeded in reaching a besieged Earth and diverting Blue Team to Onyx. However, en route the message had been intercepted by the Covenant. Newly promoted Fleet Master Voro Nar 'Mantakree of the Second Fleet of Homogenous Clarity was deployed to Onyx under orders to destroy all UNSC forces and recover any Forerunner artifacts.

Blue Team and the Covenant Arrive
Blue Team, composed of Will-043, Linda-058, and Fred-104 arrived at Onyx aboard the commandeered Bloodied Spirit, but were forced make their way down to the surface in a Spirit when their ship was attacked by Sentinels. Linking up with Kurt-051's group they planned to attack Zone 67. Using the Spirit they flew into a crater and discovered a Forerunner city.

In the same time, 'Mantakree's force, formed around Incorruptible, began nearing Onyx. Far Sight Lost was sent ahead to scout the environs but was quickly engaged and destroyed by Sentinels. Another scout, Absolution, was ordered to perform a precision slipspace jump to the northern polar areas of Onyx, but the Sentinels followed it through slipspace and Absolution was destroyed upon exiting slipspace. However, sufficient information had been gathered and 'Mantakree ordered his ground troops to converge on Zone 67.

Battlegroup Stalingrad
Shortly after 'Mantakree had engaged the Sentinels the arrived by slipspace from Earth. The Prowler provided advanced intelligence for Battlegroup Stalingrad that arrived shortly thereafter. Intending to catch the enemy off guard, the UNSC force homed in on a group of Covenant destroyers and destroyed all but one destroyer. The was sacrificed to preserve the  from plasma fire from the lone destroyer. Escape pods from the Glasgow Kiss were used to intercept three of the four lances of fire.

Despite taking multiple hits the Covenant destroyer fled to the other side of Onyx, leading the UNSC force into a trap of twenty additional Covenant warships. Several more Covenant destroyers were eliminated, but the launch of a massive plasma volley forced the UNSC ships to accelerate into the attack and close the distance to forestall a second volley. Only five UNSC ships survived the charge, of which one, the, was destroyed when she collided with enemy ships, destroying a further two Covenant warships and damaging six more in the ensuing explosion.

Defeated once more, the remaining Covenant ships withdrew again to the opposite side of the planet but were there attacked by Sentinels who used plasma capture to destroy yet another three destroyers. Realizing their peril, the Covenant ships began to withdraw from Onyx's gravity well. Two ships were used as a rearguard and one was destroyed. 16 ships escaped in all.

The intervention of the Sentinels allowed the UNSC ships time to regroup around Onyx's moon. There Dusk laid a minefield of 14 HORNETs, each rating at thirty-megatons with vacuum enhanced loads. The UNSC warships then opened fire from behind the moon, hitting some of the enemy but causing negligible damage, but drawing the Covenant's attention. As the Covenant closed to engage and entered the field the HORNETs were detonated, destroying all but four of the remaining Covenant warships. Two of these were immediately set upon by the UNSC and destroyed. The remaining two whipped around the moon and as battle was about to be joined again, a Covenant fleet of 32 ships arrived from slipspace. Battlegroup Stalingrad was completely destroyed, except for Dusk, in the one-sided engagement that followed.

Retreat to the Shield World
While the UNSC and Covenant fleet fought in orbit, in the Forerunner city Kurt-051's group of survivors were engaged by Covenant troops led personally by Voro Nar 'Mantakree. The Spartans (both II's and III's) held off the enemy advance while Halsey, aided by Kelly-087 and Mendez, configured Onyx's teleportation grid, there means of escape. Dante-G188 was killed rescuing Fred-104 from plasma and Needler fire. Once the teleportation grid was functioning, the humans moved to the Sentinel Production Facility near the north pole in the aim of destroying it. At the advice of AI Endless Summer, this would save Battlegroup Stalingrad. Halsey identified three key structures in the facility and they were destroyed by tricking Sentinels into firing on them.

Kurt-051 and his team arrive at Team Katana’s holding area to find them in some sort of cryo-slipspace containment cells. There are eight such containers, five of which contain Spartan-IIIs. They travel to the Core Room Antechamber, where they prepare to hold off a Covenant invasion force from a small tower. The Covenant have three Hunter pairs, Elites from the E’Toro, R’Lan, and N’Nono warrior crèches, and plenty of other troops. First, they send two hundred Grunts to distract Kurt-051 and company, while Elites set up stationary shield generators. There were three groups of thirty Elites and one Hunter pair behind each shield. The Elites form a line and advance behind Jackal shields. Kurt-051’s group used grenades and  snipers to counter. When the Elites and Hunters approach the stairs, Kelly-087 detonates LOTUS mines placed on the first step, killing several Elites and dazing two Hunters. Kurt-051 kills one Hunter, but the other manages to duck behind its shield. Kelly-087 engages three sword-wielding Elites, killing all three, but is flanked by two Hunters. Holly-G003 sacrifices herself to save Kelly. Kurt rushes forward and a Hunter slashes him with its shield. Linda-058 puts a round into the Hunters midsection, and then Will-043 engages them both in hand-to-hand combat. He kills one, but the other shoots him which resulted in the death of Will-043. Fred-104 kills the second with a well placed Jackhammer missile.

The Covenant forces pull back. Hundreds of Elites, Banshees, and Grunts prepare for the main assault. Kurt-051 orders all other personnel through the core and into a Micro Dyson Sphere. Kurt-051 stays behind, and after the rift closes, the Covenant approach. Voro approaches, intending to kill Kurt-051 and then reopen the rift, when Kurt-051 detonates the two FENRIS nukes, killing himself, Voro, and the entire Covenant force in the Core Room Antechamber. The others that went through the portal were not harmed, but put into a massive forerunner safe heaven that could protect the from them the covenant and halo activations.

Results
The entire Covenant Force is destroyed when Onyx is revealed to be built atop trillions of Sentinels, which promptly open fire on the covenant fleet to protect the mini Dyson Sphere inside a slipspace warphole in the middle of Onyx. The "Dusk" escapes before it, too, is obliterated.

Space

 * Human
 * Fleet Admiral Sir Terrence Hood
 * Admiral Carl "Buster" Patterson
 * Vice Admiral Danforth Whitcomb
 * Commander Richard Lash
 * Lieutenant Joe Yang
 * Lieutenant Commander Julian Waters
 * Lieutenant Commander Xaing Cho
 * Lieutenant Bethany Durruno
 * Lieutenant Junior Grade Fred SPARTAN-104
 * Petty Officer Second Class Will SPARTAN-043
 * Petty Officer Second Class Linda SPARTAN-058
 * Covenant
 * Xytan 'Jar Wattinree
 * Voro Nar 'Mantakree
 * Uruo 'Losonaee
 * Zasses 'Jeqkogoee
 * Y'gar 'Pewtrunoee
 * Ship Master Qunu
 * Kwassass

Ground

 * Human
 * Lieutenant Commander Ambrose / Kurt SPARTAN-051
 * Lieutenant Junior Grade Fred SPARTAN-104
 * Senior Chief Petty Officer Franklin Mendez
 * Petty Officer Second Class Will SPARTAN-043
 * Petty Officer Second Class Linda SPARTAN-058
 * Petty Officer Second Class Kelly SPARTAN-087
 * Petty Officer Second Class Lucy SPARTAN-B091
 * Petty Officer Second Class Tom SPARTAN-B292
 * Petty Officer Second Class Holly SPARTAN-G003
 * Petty Officer Second Class Ash SPARTAN-G099
 * Petty Officer Second Class Dante SPARTAN-G188
 * Petty Officer Second Class Olivia SPARTAN-G???
 * Petty Officer Second Class Mark SPARTAN-G???
 * Dr. Catherine Elizabeth Halsey
 * Endless Summer AI#4279
 * Jerrod "Micro AI"
 * Covenant
 * Voro Nar 'Mantakree
 * Paruto Xida Konna
 * Waruna Xida Yotno

Ships
UNSC Covenant
 * Battlegroup Stalingrad
 * , Carrier
 * , Destroyer
 * , Destroyer
 * , Destroyer
 * , Prowler
 * Beatrice, modified
 * Beatrice, modified
 * Incorruptible,
 * Sublime Transcendence, Covenant Supercarrier
 * Absolution, Covenant Destroyer
 * Bloodied Spirit, Covenant Destroyer
 * Far Sight Lost, Covenant Destroyer