Castor's chest continued to burn like a supernova as he looked at his sergeant and his captain, the man sitting down by the base of a tree. His twin hearts raced and his mind flooded with ideas of what to do next, what to do about this mess, what to do to prove to his brothers what he knew he had seen and what it meant was true. Castor had suspected Sirus of leading their chapter into a death-trap for a while, it was the only logical explanation he could come up with.

Why send fully armed Battle Brothers to the enemy for negotiations instead of baseline humans? Why, when things went wrong, did he not send the patrol detachment to the surface of Mandalore below and set up a vanguard while they were weak? Why wait for the remnants of the Chapter and its allies to amass in full while the enemy prepared? Why, in the name of the burning throne itself were they on this damned planet alone hunting for a Xenos witch instead of fighting the war Sirus himself had started?

He knew Sirus wasn't an idiot, wasn't some sword-for-brain fool who ran headfirst into wars without planning or understanding. He knew Sirus as the tactical genius he was, he was the Astarte who saved an entire world from the predating Tyranid Hive Fleets with but one company. He was the man who drove back a Black Legion speartip on the world of Thrasha Primaris. He was the man who brought down Warboss Gulggob Killshokk with but a single swing of his sword.

He knew Sirus wasn't some optimistic, merciful Rogue Trader whose own kindness and coin killed them more often than not. Sirus was merciful to the baseline humans whom they were tasked with protecting, and to the misguided but not yet damned, the entire Chapter was. But it wasn't to the point of stupidity or worse, willful ignorance. It never was.

It was like something changed, something inside him. He wasn't the same anymore, or rather his motives weren't. His skill, his intelligence, his sheer power were all the same, all unchanged, but instead of working with his men it was like he was working against them. Against them…
Castor almost aimed down his bolter right then and there as the realization struck him like a meteor. His eyes went wide as he remembered what happened only a year ago. Before they were recalled to the Xek Tek sector, before they were slung into this throne-forsaken galaxy, they were engaged with one enemy, an enemy their chapter had known far too well for centuries.

Their bronze and bone white armor seared into the young marine's mind like a brand, how could have he forgotten them? They were the last piece, the first domino that fell and led them to where they were now. They were the 8 bound cursed sons. The bringers of corruption and sorrow. They were their cousins, twisted by the Gods of Chaos and their malevolent machinations.

They were the Apostles of Blood. They had once been a chapter of Astartes the Angellis Mentors had fought alongside for centuries. Descended from the bloodline of Sanguinius and his noble sons, they were once proud and stalwart Astartes. However, a flaw known to only a few persisted inside their ranks, one that had wracked all members of the Blood since Sanguinius's fall to Horus himself. A dark, creeping mental and genetic trap. The Black Rage. One day, the Chapter's leadership simply couldn't deal with it any longer. More and more of their number were succumbing, more and more needed to be culled, it had gotten to the point where their recruitment simply couldn't replenish their numbers fast enough anymore. Their number went from 1000 strong to only 400.

So, they turned to a new tactic. Their librarians, reaching far into the Warp itself communed with the Dark Gods, promising respite and safety from the ever-present darkness. In a moment of doubt, they accepted, damning themselves and their legacies forever more.

The last real fight they had was between them, and like always, they took heavy losses from their fallen kin. However, the thing that made Castor come to his realization, the thing that made his twin hearts skip a beat was this. Sirus was captured by their lord during the battle, and held for weeks before being rescued by the rest of the Chapter. This had to have been the source of his behavior, it had to have been. The damned Apostles did something to him, turned him from the Emperor's light, and it had only started manifesting itself when they reached this galactic disk.

It was the only real explanation he had. He wanted to kill Sirus then and there, give him the Emperor's Peace and free him from whatever had taken him over, but he knew he would fail utterly. The captain's armor was strong enough to withstand a few bolts, not to mention his Iron Halo's refractor field. The men around him would turn on him instantly too, he'd be dead in seconds. Castor placed that thought to the back of his mind, he needed a better idea, he needed to convince them that Sirus was corrupted.
Castor's twin hearts began to race as he finally remembered. The fight, and the cowardice Sirus uncharacteristically displayed, were all recorded by his helmet's internal cogitator. Every engagement the Marine was in was. He had proof, all he needed to do was show them. Sure, it wasn't enough to definitively prove his corruption, but it'd be enough to put his fellow Astartes on edge, and it would mean if and when Sirus slipped up again and showed his true colors, he'd be taken care of.

Castor's thoughts were interrupted as Sirus himself spoke to his men, voice booming throughout the cold night.

"Men, gather your equipment. We move out soon." Sirus began.

"What's our plan, Brother Captain?" Tabit replied, hefting his bolter over his shoulder.

Sirus grit his teeth under his helm. He wanted to just place himself and his men back on the path below, allow the rest of his soldiers to be massacred so he could finish his business here on this forsaken planet, but that obviously was out of the cards right now. What wasn't, however, was the possibly equally as suicidal push he had created with Aiolos.

Aiolos wasn't the brightest sergeant. He was smart, yes, but he was easy to manipulate, easy to toy with. His idea, on the surface, was one that would have completely derailed Sirus's plans, but with enough pushing, it worked almost as well as the plan before.

"I believe we may have found the source of this Sorcery-induced loop. Aiolos, using the Auspex Scanner, managed to locate a point of central energy of some kind. It's barely half a click from here, back west from where we came. We blindly ran into this trap in our haste to stop this madness, expecting to find the Xenos Warlord behind this here, and we paid for it with one of our own." Sirus went silent at that, feigning a sudden, all too artificial guilt.

"I should have been leading you better from the beginning. Our tactics will change from here on out." The man stated. Everyone around him seemed to buy it, all but that troublesome Castor. Sirus silenced that thought. He knew Castor would be dead by the end of this anyways, and he knew whatever the stubborn meddler had planned would fail as soon as he attempted it.

"What's our plan then?" Izar asked. "Running into battle blindly is not an option anymore. It worked against the mercenaries, but knowing the enemy has these sorts of constructs now does not bode well for that tactic anymore. We already lost a man to that."

"I agree, we can't do what we did before." Sirus exclaimed. "That's why I will be the one to scout ahead of the group. I will figure out what exactly we are dealing with, and what enemy armaments and troops are guarding this target. With any luck, I will be able to ascertain their strength and numbers. Once that is done, we will commence a more careful and thoroughly planned assault."

Castor's blood went cold as he heard Sirus say this. This was a trap. It had to be a trap, he was going to lure them all into another meat grinder and get them killed in the process. Castor stood back up, calmly walking over to his squadmates as Sirus finished talking to his men and departed, coordinates beamed to his helmet via Aiolo's Auspex. Castor felt something he didn't know how to describe then, a quickening of his twin hearts, a sudden rush of adrenal hormones throughout his system in a way he simply couldn't describe. He realized what it was as he came face to face with the remains of his squad, Aiolos joining them immediately after he did.

Was this fear?

Castor was jolted from these thoughts as he remembered what he needed to do, the apparent feeling turning from a sinking dread to a familiar need, a want, to stop the coming death and mayhem.

"This is a trap. I have proof." Castor proclaimed, stretching out his left arm, holding his Mark-3 helm in his hand. The men around him simply stared at him in response, even Izar.

"Are you well, Brother Castor?" Aiolos said in response, his words like a serrated blade jamming into Castor's guts. Castor slowly lowered his outstretched hand in response. "That was a question, Brother Castor."

"Yes. I am well. I know what I saw, you have to believe me. We are walking into a trap, we are going to be torn apart by the enemy and Sirus will just watch from the sidelines." As Castor spoke the lumbering form of Tabit walked over to the ranting marine, his Mark-5 power armor, studded and ancient brushing up against his brother's Mark-3, his form slightly taller than the man he was about to trade blows with.

"Like you watched Ogma die and did nothing?" Tabit said, anger literally billowing from his every word. "You are a hypocritical, lying rat. If it wasn't for the fact that we are now a brother short, I'd have no issue with wrenching your head off of that armor you never earned in the first place."

"You're being a fool, you all are! I have the proof right here, recorded by my helm's cogitator, I have pic captures of him simply watching us!" Castor exclaimed before a gauntleted fist hit him straight in the jaw, causing the marine to tumble down onto his knees. Tabit stood over his increasingly estranged brother, red helmet lens burning with hate and grief.

"He was my brother! He was worth at least 50 of you, if you were fighting with us he would be alive right now, his duty would have not yet been done!" Tabit screamed at Castor, the marine coughing up blood and teeth as he remained on all 4 limbs. As he did so, the form of Izar stepped between the two yet again.

"Stop this!" The sleekly armored marine roared, the forest around them silencing itself. A few, awkward moments passed by as Tabit stomped away, leaving Castor's form to reassert himself, pulling himself back up from the dirt and mulch-covered ground. As he did so, Izar began to speak again.

"You. Castor!" Izar gleamed at the form of the youngest Astarte, blood spittling from his mouth as it coagulated and sealed the spaces where a number of his teeth used to be. "I don't care what proof you have, I don't care how solid it is, you can show us when the nerves of this squad are cooled when what happened before is simply a memory. Your crusade is wrenching this squad apart!"

"And you, all of you!" The enraged marine screamed towards the forms of Tabit and Aiolos. "You might not want to think of the possibility of Sirus turning against us, but like it or not, it's entirely possible. His actions ever since we arrived in this galaxy have been strange. Maybe it's stress, maybe it's simply his new-found responsibilities getting to him. But we cannot, not ever, discount the possibility of betrayal!"

"Why would he ever turn on us? He is the best of us!" Tabit raged in retaliation.

"Horus was the best of the Primarchs, you fool! Look how far he fell himself. It's entirely possible Sirus is loyal, likely in fact, but have you forgotten the grave lessons millennia of betrayal and death have given us? Trillions of lives have been paid to pass that lesson along! Trillions! We must stay vigilant…" Izar continued. "But not to the detriment of us all." The man finished as he peered back at Castor.

All Sergeant Aiolos could do is sigh in response, before begrudgingly agreeing. "Izar is right. There is no proof as of now of Sirus's treachery. But we must. Must. Stay vigilant. But we must not lose sight of each other."

"What about Castor, and his so-called 'proof?'" Tabit asked in response, his emotions still very clearly burning like fallen embers.

"We will review it once we are out of this loop, and we are alone." Aiolos was about to finish before he was cut off by Castor, his voice gruff as he attempted to talk clearly and concisely with his missing teeth.

"Why not now?" Aiolos looked back over at the now-standing form of Castor as the man asked this.

"Because we have an assignment to do. Our duty always comes first, always." The sergeant answered. Dejected, Castor simply clipped his helmet onto his belt before nodding solemnly in response.

"Now, form up. We need to get moving."