Most of what is known about Karslan the Annihilator comes down through myth and legend. Being that he lived ten thousand years ago, it is only natural that his story may have become exagerated over time. But as the Tarsins tell it, this is his tale:
One of the most notorious and over-the-top figures in the Coalition's history, Kônǔsôs Karslan was larger-than-life even when he was alive. He grew up in the days of the founding Emperor's war to unite Tarsis once more, and by the time he was an adult, he had already caught his liege's attention for his spirited way of doing war. Karslan was the first of the Emperor's team of brilliant commanders and warriors he would use to bring order to the new Empire.
Karslan was given the rank of Fleet Lord, and told to carry on the Emperor's reconquest in the opposite direction. Within a few years, Karslan had pulled off a series of very risky and daring victories, as if to prove a point, though to whom no one could say. He only gave enemies his terms once; immediate surrender or else. Or else would be the brutal conquest and pillaging of anything he and his troops wanted. Usually, Karslan only had to utterly annihilate one of the petty kingdoms of local warlords to make the others fall in line, but that didn't stop him from going to town on anything that remotely offended him. His policy of "ask no mercy, give no mercy" and its application to entire cities earned him a black name amongst those back home.
By the time word reached the Emperor of one of his best commander's atrocities, it was too late to do anything. Karslan was thousands of light years away, and with so few etherspace beacons yet recovered, communication was impossible, let alone the possibility to physically find him. So, Karslan's adventure of destruction continued; he merrily plowed his way deep into the chaos of the post-cataclysm World. It was said he personally fought against evil constructs that had taken over planets, and that he even bested several in combat. It was said he executed his enemies with his own gun, and that he enjoyed fighting them to the death if they were skilled enough to challenge him. It was said that he drank the blood of his foes, that he wore a monstrous skull over his face just to scare people, that he had horns, that he could shoot fire from his hands, that he was the son of a demon, that he killed said demon and ate its spirit to enhance his own, that he kept ash from every city he bombed to dust in jars that lined his chambers aboard his flagship, that he was an accomplished musician and songwriter, and that he had never lost a game of dice in his life.
Now, obviously, some of these things never happened; the Tarsins admit as such. But it is a testament to either his reputation or his propagandists that such theatrical tales survive to this day. No account of the reconquest is complete without the infamous image of Karslan presenting the pile of his foes's heads (long since turned to bare skulls) to the Emperor when they finally met again, many decades later. Popular tellings of his tale hold that Karslan the Annihilator died of stroke back on Tarsis while yelling at local orphans causing ruckus.
Today, Karslan is a reoccurring character in Tarsin literature and folktales, usually the source of some ancient curse or wrongdoing which a hero would need to set right. Though not well-regarded, he does have the thanks of his descendants for helping secure the Empire's early days, and the immortality in memory that comes with it, much like his other, nobler comrades of those days.