Skirmish on Minor Transgression
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The Skirmish on Minor Transgression was the disastrous first contact between the Covenant and humanity. It took place on a human freighter, Bulk Discount and the Covenant vessel Minor Transgression in the Epsilon Indi system near Harvest on January 17, 2525.
Over a short amount of time, the Covenant had boarded several unmanned human freighters in the Epsilon Indi system. At the same time, insurrectionists bombed National Holiday over Reach, resulting in over a thousand deaths, and the United Nations Space Command decided they would not allow the insurrectionists any more victories. After the disappearance of the manned freighter This End Up, the Office of Naval Intelligence authorized an investigation into the matters, expecting that insurrectionists were the boarders.
Jilan al-Cygni, an ONI agent, set up a trap for the boarders: lure them to an unmanned freighter over Harvest and ambush them. Two UNSC Marines, Staff Sergeants Avery Junior Johnson and Nolan Byrne, both of whom stationed at Harvest to train Colonial Militiamen, were to ambush the expected Insurrectionists. Al-Cygni had an arsenal of weapons onboard her ship, the UNSC Walk of Shame, including some prototypical XBR55 Battle Rifles. Walk of Shame itself was armed with one Archer Missile. 
Johnson and Byrne, armed with XBR55s and outfitted with vacuum suits, moved into position but quickly saw that the boarders were not insurrectionists: they were four Kig-Yar. Johnson asked for further orders, and Al-Cygni ordered that they continue to engage them, but they should try to capture one, and under no circumstances should any be allowed to escape. The two Marines engaged the aliens: Byrne wounded one, but was wounded by another Kig-Yar armed with an energy cutlass. Johnson shot another and killed it with its own blade. Johnson tended to Byrne's wounds and finished off the wounded Kig-yar. Shipmistress Chur'R-Yar, retreated onto the Minor Transgression; Johnson followed her and then killed her. He then left Minor Transgression, which was destroyed by Chur'R-Yar in an attempt to cause to ship to self-destruct. Only two crew members survived the blast: the Deacon Dadab and the Huragok Lighter Than Some, who fled the ship in an escape pod.
After the battle, the UNSC tried to make peace with the Covenant through pictograms. However, this failed when the Covenant leadership learned that the humans were somehow connected to the Forerunners. Thus, the new triumvirate of Hierarchs soon decreed that humanity must be exterminated in order to preserve the foundation of the Covenant.
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