Deep beneath the palace of Terra, in a vault hidden from all save for those entrusted to make sure that what was within never escaped, a figure waited. Some would say that given the sheer size of the figure that such an action could not fully encompass what it was doing. To be sure, it was massive, titanic in scope and scale. A creature of living metal and patterns. At one sacred and profane. Much like its father, it was incarnate. Though an incarnate of what, that was the question, wasn't it? Opposing concepts, made without understanding, without full knowledge save for desperation.

Some would say that its true form would merely be a pod inside of itself. The last dregs of humanity, something maintained less because it was necessary and more because of regrets. He had never intended this. It was bad decision after bad decision borne of terror and panic that had resulted, in the end, in him becoming something that the Emperor could not, would not, ignore or tolerate. But neither would he be destroyed, as he had went into imprisonment willingly. Or at least had been subdued so easily that many of his wardens were of the thought that he had accepted his fate.

And so, he sat in the dark, still and silent. Until a head rose, eyes gazing at something beyond sight. Several of the wardens saw in that moment wings of night, of voids complete and total as he rose, despite the fact that their prisoner should not be able to move. Symbols tore into reality, emptiness carved of unmeaning, a door opening, a oath leading somewhere. And from beneath the Imperial Palace, a titan walked to war. There had been no approval, no orders of dispatch. And yet, it had left as if there had been no wards, no means of holding it in place.

Thankfully, or perhaps not, it did not exactly go far.

Horus

The world howled, even as something moved, appearing over the battlefield like some grand idol. In shape it was like a man wearing armor, a scythe in one hand held more like a staff. Wings were at its back, symbols of utter void, of collapsed meaning and understanding, of utter emptiness forming wings behind it, even as a blank face looked out. Angron roared, rushing forward to meet whatever was unleashed. "Brother."

The voice was a carving thing, a scything claw that left meaning in what it tore out, the aura of a pariah of monstrous and absurd power reaching out. And yet, from that word, as he looked on, blood turning into ice, was this actually? "Cease your rage. It will avail you naught." The tone was cold as the shadow expanded, Astartes dropping as if puppets with their strings cut were it touched. "You have been consumed by the primordial annihilator brother. Allow me to grant your shell mercy."

The monstrous angel floated forward, power flickering and fading, a zone of darkness and silence around it. There was no violence, no unleashing of weapons. Life simply could not exist inside of its shadow. Angron, consumed by rage, burned and froze, ice and fire on the edges of the storm. And yet the Daemon Prince was being flayed, ground down as he tried to reach whatever it was in front of them. And yet, one moment there was fighting and the next?

Angron was in the grip of the thing, looking up with relief in his eyes. "Is it over?" There was weakness in his tone. "Am, am I finally free?"

The creature held the weapon in its arms. "Indeed brother. Rest in peace." And so the Red Angel closed his eyes, as silence fell, the nails coming undone. There was a roar of rage, Khorne incensed at losing his champion, the body of a mortal primarch taken from the gore and placed with almost tenderness into a safe place. Wings extended, and the dark angel began to move once more.

Big E

He felt a headache as the Eleventh had left its vault. Where apparently, it had been capable of leaving at will and was only now emerging to wreck havoc for reasons that escaped him. Because in many ways, he was insane, the results of somehow undergoing bio-transference while infusing his soul back into himself using wraithbone links to literally make himself some sort of living metal psi-titan. Some sort of blank psi-titan instead of one that used more standard psychic energies. And even before that the eleventh had a habit of doing stupid things because he had only a rough half idea of how it all worked and no fucking idea of the consequences.

And now there was a literal angel of death flying around and reaping the traitor forces. You know what, he would take what he could get at the moment, as flowers of silence bloomed, Death Guard being consumed by the abyss, souls dragged into a furnace as something built up. He hoped that it was something that the eleventh actually knew he was doing. It would be just like the idiot if it was some sort of automatic reaction that would end with him blowing up. Now, deep breathes, deep breathes, as he had a few plans to try and rehabilitate the Eleventh after all of this was over. Not as originally planned of course, but...

Ah, and that answered if he was aware of the energy build up, given the void beam that just sliced a ship in orbit in half. Granted, from the looks of it, it took a while to charge, so he did not have an unlimited number of anti-orbital strikes. Still, he now had to answer, or fend off answering, some awkward questions as to why there was a titan sized null-titan shaped like an angel flying around that was calling the primarchs brother.

Because that would raise the question of, if one of the sanctioned had been HERE all along, where exactly was the other and what exactly were their crimes. Little questions that he did not want to answer at the moment and could prove disruptive to unity.