[You breathed in the cold, damp air of the cavern and moved.]
[Both feet came down in sequence, each impact leaving a cracked crater in the hard stone floor, the force of your launch transmitting through the ground and outward with every stride. The craters were not small. Neither was the speed at which the distance between you and Magnus was closing.]
[He did not wait for you to arrive.]
[The psychic spells came in a continuous stream, each one conjured with the offhand ease of someone who had been doing this for centuries and found the exertion genuinely minimal. They tore through the frigid air with visible force, the psionic discharge leaving burn trails across the stone where they missed. You read the angles as they came and your body moved before your conscious mind had finished processing each threat, your superhuman senses pulling you left and right and under the lines of attack with a precision that surprised even you.]
[The ones you could not avoid, you took.]
[The scales adapted.]
[You noticed it happening in real time: where the psionic energy struck the diamond-pattern scales covering your body, the scales did not simply absorb the impact and hold. They processed it. Each strike left the affected scales denser, the color deepening from their initial iridescent state toward a consistent deep blue, the defensive quality of the material upgrading itself with each successive hit as though the psychic bombardment was feeding the very mechanism meant to resist it.]
[By the time the scales had fully shifted to blue, Magnus's standard psionic output was accomplishing very little.]
[He noticed.]
[The Crimson King's expression shifted from contempt to something more engaged, and he stopped generating spells at range. His massive body surged forward instead, psionic smoke curling from his bronze skin and red hair as he closed the distance, and from his palm a weapon condensed out of raw psychic force: a crimson spear, the shaft and head assembled from solidified psionic energy, crackling at the edges.]
[You swung the tentacle arm.]
[The extended limb, covered in its rings of suction cups, went out fast and hard across Magnus's body, the impact shattering sections of his ornate armor. Magnus did not try to dodge it. He took the hit and brought the crimson spear down toward the top of your skull in the same motion.]
[You dropped your shoulder into the path.]
[The spearhead went through the shoulder plating and through the blue scales and into the body beneath, the penetration clean and complete, the pain registering as information rather than sensation. You processed it and did not stop moving.]
[The tentacle arm was already looping back around Magnus's waist.]
[It pulled.]
[Magnus came with it, the meters between you collapsing as the tentacle hauled his full mass toward you, and the bone-spiked iron fist was already moving when he arrived. The fist drove into his ribcage and through it, the bone spikes finding the space between the armor segments, and for a moment the two of you were face to face at a distance of centimeters, his single eye and your blood-red reptilian ones regarding each other with mutual attention.]
[Magnus raised his other hand.]
[The grimoire came from his waist and hit the side of your head with the full force of a Primarch's arm behind it, the psionic energy stored in the binding discharged on impact. Most of your face on that side ceased to exist in any organized sense. The blue scales and the flesh beneath them were gone in the explosion, along with one eye. You felt this as a loss of sensory input and nothing else.]
[You grinned with what remained of the relevant facial musculature.]
[The bone-spiked fist withdrew from the wound it had made and the tentacle arm tightened and lifted, pulling Magnus off the ground entirely before slamming him down onto the stone floor of the courtyard on his back. The shockwave from the impact spread outward as a visible ring, the stone cracking in a radius around the point of contact.]
[Magnus hit the floor and lay still for the fraction of a second it took his extraordinary physiology to process and respond to the impact, and in that fraction of a second he brought the crimson spear across in a sweeping cut that caught the extended tentacle arm at the midpoint.]
[The arm separated.]
[You stepped back, the stump of the limb already changing, the tissue at the cut point pulling itself into a new configuration with visible speed. Within a few breaths, the mutated arm had resolved into something new: a hard, segmented limb ending in a broad curved blade, the shape functional before it had fully finished forming.]
[You breathed in the blood-and-ozone air and drove the scythe arm down toward Magnus as he was rising.]
[He caught it on the crimson spear, and the next exchange became something different from what had come before: a close-range clash of striking surfaces and angles, Magnus using the spear with the precision of centuries of practice, you using the scythe limb with the instinct of a body that seemed to know what it was doing even when you did not. The sounds of the exchange rang off the cavern walls and across the lake surface.]
[Across the courtyard, the fight between David and the four Thousand Sons Astartes had been running its own course.]
[The four had been working in a coordinated psychic formation, cycling their combined output through a mandala pattern that kept the pressure on David from every angle simultaneously. David had been absorbing it, processing it, looking for the seam in the pattern. He found it.]
[His eyes lit blue and the nanomachine-constructed body moved, the mass of it dropping into the gap in the formation at a speed the targeted Astartes could not react to. The result was immediate and final. What had been a Thousand Sons warrior was distributed across a wide area of the courtyard floor in the aftermath.]
["How dare you—"]
[Magnus felt it through his psychic perception the moment it happened. His concentration fractured, just for an instant, the spear's coverage dropping by a margin that was small in absolute terms and decisive in context.]
[You saw the gap.]
[The scythe arm drove through it without hesitation, passing inside the spear's guard and coming down across one of Magnus's arms at full extension.]
[Magnus screamed.]
[The arm came away from his body at the shoulder, the crimson spear still locked in the palm's grip, both of them tumbling away together through the smoke-and-blood air, psionic energy bleeding from the wound in wisps that curled upward and dissipated into the cold of the cavern.]