I was there at the Council of Nikaea.

I was there when the Emperor issued his infamous decree banning sorcery from use in His Imperium.

I was part of Magnus's honor guard, a Sehkmet Terminator along with eight others and Ahzek Ahriman. We thought Nikaea was a place where we could debate and deliberate with others regarding the ideals of the Thousand Sons. We were wrong. Nikaea was a place of condemnation against the XV Legion. I listened with horror as Mortarion, primarch of the Death Guard, railed against our ways and stained our Legion's honor with insults and slurs. My horror turned to disgust when a Space Wolf I did not know took the podium and cast unforgivable curses onto my brothers. My disgust turned to hatred when time and time again, witch hunters and naysayers rose from their seats and showered us with venomous words and barbed jibes.

These people do not understand, I remember thinking to myself all those years ago. They are unenlightened dullards who will never rise above their fears. We had calmed the Great Ocean. We could discern through the future at will. Our cults knew the aspects of sorcery as well as they did the back of their hands. What madness was this, that these barbarians would cling to their old ways and criticize us for walking another path?

Then, it came Magnus's turn to speak.

I had not known my primarch was capable of such speech, but the evidence was undeniable to my ears.

Magnus stood resolute and unwavering against the baleful stares of his naysayers, his golden armor glinting with torchlight. He launched into a stirring oratory that would have made Lorgar bow his head in shame. Magnus spoke of the need for the Imperium to be an empire of knowledge and understanding, not a dominion of the unenlightened and the ignorant. He spoke of how sorcery could be tamed to the touch of pyskers, of how the Great Ocean could benefit all mankind. He turned aside the accusations of witchcraft and heresy with tempered logic and cool reasoning, winning the hearts of many within that council room.

I felt my twin hearts beat faster at every word that came from my father's mouth, proud that my blood came from such a brilliant being. On that day, as I listened to my primarch speak, I felt my love for him soar higher than ever before. Through speech, Magnus had described what it meant to be a warrior of the XV Legion.

The Age of Strife had cost humanity dear. Knowledge was lost on a galaxy-wide scale, scattered into ashes in the countless civil wars that divided mankind.

The Great Crusade ended the strife and discord between factions of men, but it also brought with it the Imperial Truth. Religion was banned in all of its forms, ancient books and sacred texts along with it. The Thousand Sons seeked to prevent such atrocities from occurring. To us, knowledge was power. Enlightenment would allow for humanity to span the stars, and it was our wish that the Imperium we shed blood to build would not demur from this fact.

Knowledge, and the quest for it, was what we thought necessary for the race of man.

We were wrong.

In the end, Magnus's brilliant oratory was of no use. The Emperor reached his decision regardless of my primarch's pleas and banned the use of sorcery from the realms of man.

I had been shocked then. Too shocked for words. I had thought, along with my brothers that our father's speech would be sufficient to sway the neutral to our side. We were confident that our condemners would see the folly of accusing us and would soon be forced to drop their venomous charges altogether. Instead, it was we who were defeated. The just slandered by the vile. The enlightened spat upon by the ignorant.

Our voyage back to Prospero was a gloomy one.

As our spaceship sailed through the cold void of space, I felt the betrayal by my fellow man like a wound on my skin that refused to heal. How could Space Marines cast slurs against a fellow Legion? How could Mortarion, esteemed father of the Death Guard, spout insidious lies towards Magnus? Were not the primarchs closer in brotherhood than even we Astartes?

I could not comprehend it then. I still can't comprehend it now.

More worryingly, the ban of sorcery in the Imperium would irrevocably change our Legion.

I do not expect you to understand. Our way of war was not like those of the other Legions. We did not butcher mindlessly like the World Eaters. We did not construct great fortresses on our battlefields like the Iron Warriors. We did not hit and run like the Raven Guard. Sorcery, the use of unmitigated Warp power, was the way the Thousand Sons destroyed the enemies of man.

To ask of us to abandon sorcery, was like asking a dog not to bark, a fish not to swim, a bird not to fly. Sorcery was our way, and it was molded into our lives just as it was molded into our way of war.

Perhaps this was the reason why we fell from grace those thousands of years ago.

When we arrived on Prospero, Magnus stalked into his inner chambers, followed by the closest of his advisors. There, they would deliberate on the ruling of the Emperor and how it would apply to the Thousand Sons. The primarch and his closest sons did not come out for many weeks. When finally Lord Ahriman emerged from the pyramid towers that were Magnus's haven, I was the first to greet him. I asked him of our father's health and questioned what was to be done regarding our Legion's purpose. The banishment of sorcery from our arsenal had affected us deeply, and many of us did not know what next to do.

Ahriman's response to me would prove prophetic for the dark days to come.

"Events have been set in motion that even we cannot change, brother," he had told me, "Hope that the Great Ocean is responsive to our pleas. Otherwise, I fear that damnation may be ours."

Before I could question him further, he brushed past me, his attention focused on more important matters.

I did not take seriously Ahzek's words. The thought that anything could threaten a whole Space Marine Legion was laughable. We brought the entire universe under the heel of man, put to the sword countless xenos species, and united the fractured factions of humanity into an empire never before seen. We could not be defeated. The only beings that could match us in skill and valor were our fellow brothers in the other nineteen Legions. But they would never turn their weapons against us.

Or so I thought.

Thanks for all the reviews! For this fic, I'll keep my responses short and will reply only to questions. That being said, I'm not ignoring my faithful reviewers!

Gree: Yes, I realize that the Alpha Legion is most likely corrupted. However, it is my belief that at least some of them still follow the decree of Alpharius and do secretly fight for the Imperium.

Peanuckle: Yup. Its me posting on /tg/.