From the Journal of Alexander Achilleus

"As the Imperium Of Faunus established itself as the new dominant superpower in Remnant, some people never seemed to get the message. The worst case of denial was Theron Saresh, an Atlesian Admiral who'd somehow escaped the Sacking of Atlas. He had taken control of an Atlesian Warship called the Resolute and led several attacks on Imperium convoys. The Imperium eventually tracked down the Resolute all the way to the ruins of Atlas. I was assigned with the rest of the 13th Legionis Imperatorie to wipe out the Atlas holdouts. It seemed like a simple enough mission."

On board a Malleator-class cruiser, Alexander Achilleus and the Faunus of the 13th Legionis Imperatorie prepared themselves for battle. As the Imperium soldiers readied their weapons, Commisarius Baelon approached his men. 

Baelon: Men and women of the Imperium! Today you take on a vital mission for the Imperium. Soon, we will approach Admiral Saresh and his band of Atlesian holdouts. The mission will not be easy, but I know you will serve the Imperium well! Long live the Faunus! Long live the Imperium!

13th Legionis Imperatorie: Long live the Faunus! Long live the Imperium!

As the Faunus of the 13th Legionis Imperatorie saluted their commander, the sound of blaster fire was heard. The Resolute could be seen firing upon them. An aerial battle broke out between the Resolute and the Malleator-class cruiser. Despite being relatively outdated compared it's Imperium counterpart, the Resolute held it's own, dealing massive damage on the Imperium cruiser. As the battle intensified, the Imperium cruiser sustained heavy damage. But just as it was about to crash, the Imperium cruiser unloaded all of it's firepower on the Resolute's engines, causing it to crash. Inside the Imperium warship, Baelon spoke to his men. 

Baelon: BRACE FOR IMPACT!

Alexander and the Imperium soldiers braced for impact as the cruiser crashed. During the crash, Alexander was knocked out. He would wake up some time later as Baelon dragged him out of the wreckage. 

Baelon: On your feet, soldier! The battle is not yet over!

As Alexander gets up and readies his rifle, he looks to see that the Atlesian holdouts had established a defensive position outside the wreckage of the Resolute. The defenses included heavy automatic cannons firing on the makeshift Imperium trenches. The bodies of several of Alexander's comrades were seen laying on the ground.

Alexander: What happened? 

Baelon: The enemy managed to recover and set up defensive positions around the Resolute. But they only prolong the inevitable!

 As the 13th Legionis Imperatorie gathered around the trenches, Baelon rallied his troops. 

Baelon: Faunus! Affix bayonets! Affix bayonets! Prepare to charge! Be ready for blood!

Alexander and the rest of the 13th Legionis Imperatorie did as they were ordered. Baelon then ordered for several smoke grenades to be thrown as to ease their approach. As smoke flooded the battlefield, Baelon prepared a sword and a whistle. After a moment of uneasy silence, Baelon blows the whistle. With a deafening roar, the Faunus of the 13th Legionis Imperatorie ran out of the trenches and charged into the Atlesian lines. The Atlesian defensive positions fired as barrage of blaster fire on the Imperium legion. Alexander led the charge and many of his comrades were cut down beside him. Alexander reached the line first and began firing on the Atlesian soldiers. 

Alexander: FOR THE IMPERIUM! 

A bloody battle broke out as the Imperium troops broke through the Atlesian defensive lines. Alexander shot down any Atlesian soldiers that crossed his path. Even as the Imperium took heavy casualties, they refused to back down. The Imperium soldiers soon entered the ruins of the Resolute and began killing all in their path. 

Baelon: Do not let up! Show these Atlesian dogs the Wrath of the Imperium! 

The Imperium charged with zeal as they slowly cleared the Resolute. The Atlesian holdouts were helpless against the relentless onslaught of the Imperium legion. Eventually, the Imperium reached the bridge where Admiral Saresh and a squadron of Atlas Commandos prepared for their last stand. During the battle, Baelon was stabbed in the chest by Saresh. 

Alexander: Commander!

Alexander charged at the Atlesian Admiral and battled him. During the scuffle, Alexander attempts to fire his rifle, but it jams. This allowed Saresh to press the attack, knocking Alexander to the ground. Just as Saresh was about to land the killing blow, Alexander impales Saresh in the abdomen with his bayonet. Alexander then got up and proceeded to stab the Admiral multiple times with his bayonet until he was dead. After killing Saresh, Alexander rushes to the wounded Baelon. 

Alexander: Medic! Medic! We need a medic now!

Baelon: Your name....give me your name.....

Alexander: Achilleus....Alexander Achilleus....

Baelon: Alexander Achilleus....fight....fight for the Imperium. 

As Baelon took his final breath, he died in Alexander's arms. Alexander soon took charge and led the Imperium legion in wiping out what remained of the Atlesian forces. In that moment, the battle was won. 

"With the death of Admiral Saresh and the destruction of the Resolute, the rest of the Atlesian holdouts were quickly wiped out and put an end to any thoughts of an Atlesian Rebellion. Now we can get about the business of maintaining an empire, rather than building one. But this glorious victory did not come without it's costs. The 13th Legionis Imperatorie suffered heavy casualties, including that of Commisarius Baelon. But that did nothing to dampen our devotion to the Imperium. Instead, it strengthened our resolves. The 13th Legionis Imperatorie survived the  brutal crucible in the ruins of Atlas, battle hardened and ready to serve the Imperium to our last breath."