Footsteps receded before him into nothingness. He watched as each palm of white light erupted on some invisible plane before vanishing, tendrils of softly glowing energy rising from each percussive mark and then fading from sight. Narrowing his eyes and peering into the dark he could make out the shadowy form of a fleeing figure, apparently the one responsible for the rippling disturbances across the even surface of the black mirror.
And then he realized he was watching himself.
It took a moment for him to register it, as seeing himself from that angle was unfamiliar to him, but it was undoubtedly his own body. Although the fact that he was observing it from the outside was troubling to say the least. He understood immediately where he was: the infinite mass of darkness around him could be nothing other than the Dangai, but he could not fathom as to what had happened to him, nor why there were now apparently two of him. And he quickly realized that the only way to find out would be to track himself down, put both of his heads together, and sort it all out.
It was, by far, one of the strangest things that had ever happened to him; and he had seen many strange things during the extent of his lifespan.
He did not hesitate a moment longer, instead taking off to chase after his other self, who was rapidly vanishing from sight. The first thing he noticed was how difficult it was to move. This was to be expected, it was the Dangai after all, and to encounter a pocket of thick, invisible matter was not uncommon. Still, it felt as though he could not get his footing, simply sliding forwards as if balancing on ice. Not only that, but there seemed to be an inexplicable pressure trying to push him back from the surface he was standing on, and he felt unusually weightless. And despite the heaviness of the atmosphere around him, and even after running for some time, he had expended no energy. He was breathing normally, he was not sweating, and his heartbeat was subtle enough to remain unheard in the silence flooding his ears.
The thin aura of light he was trailing continued to grow more and more distant. He tried to call out several times, but at each attempt his voice was snatched away by the echoing void that surrounded him. At last he lost all sight of himself, and found that he was alone. But he did not stop running. To drift away into the eternal night would be fatal, and he had long ago determined that, on the chance that he fell behind, he would do his best to reach the Soul Society on his own. Already a nagging doubt was infecting his mind. There was a heavy, insidious suspicion weighing on his chest, but he pushed it aside. He had to concentrate on one step at a time—literally. He could leave the hypothesizing until after he had escaped from the emptiness.
As he continued to forge his way through darkness, time blurred into irrelevance. He found himself stumbling as he tried to fix his feet beneath him. His senses were dulled, and could not perceive his surroundings very clearly at all. Again, he could blame the unique atmosphere of the Dangai for the phenomenon, but still that acidic doubt permeated his subconscious. He swore when he nearly lost his footing for the hundredth time, and he tried to form a basic Kidō spell to illuminate the path in front of him. But he found that it was impossible for him to focus his Reiryoku at all, and met with no result even when he called out the full incantation. Again he blamed the area of the Dangai he was passing through for stifling his Reiatsu and ability to use Kidō. But again there was a visceral twinge of unease. He knew something was terribly, terribly wrong, and yet he purposefully decided to ignore it.
It was then that he realized his Zanpakutō was missing.
He slid to a stop, allowing the deep, fluid rumblings of infinite space to close in around him. His breathing remained unlabored and even; he felt no sense of tiredness, and yet he knew he had been travelling for dozens of minutes by then, possibly hours. Extending his hand, he closed his eyes and tried to concentrate his Reiryoku into his outstretched fingers, pulling on the energy flowing around him and reaching out to the consciousness imbued in his sword. It was a basic technique, intended to call a Zanpakutō back to its owner in case the two were ever separated. But there was no response, which did not surprise him. If he had been unable to use Kidō: both an intake and outpouring of spiritual energy, it was only logical that he would be unable to draw a connection to his sword as well. At least, that is what he told himself.
He weighed his options carefully. If he turned back now, he might be able to find it, but with the endless plane of darkness stretching about him, it was an unlikely outcome to say the least. The more probable result would be that he himself would become lost, perhaps forever. But to leave his Zanpakutō behind meant trusting the blade to an unpredictable and indifferent entity, essentially abandoning a piece of his own soul, and while he had his theories as to what might occur there were too many uncertainties, too many unknowns to hope that the repercussions would be minor. He cupped his chin in his hand and pressed his teeth against his index finger— an old habit of his, and thought.
The semblance of a minute passed by, then another. It was impossible to keep track in the blank expanse of time. He may have remained there a while longer, had it not been for the sudden shift in gravity that began to pull at the center of his chest. After having been robbed of his senses for so long, the sensation startled him, and he determined to find its source. The magnetic force was calling him onwards, enticing him to dive deeply into the draw and forget all else but its ghostly embrace.
And he relented, allowing its will to slowly submerge him and pull him towards a nexus of energy that was not energy, towards a power that was void, towards the edge of the precipice. Could it have been a dimensional line? He wondered if he had found a point where the planes of existence met: a fissure between the realms.
Then a shape floated into the hollow space in front of him, although he was not consciously aware of when it had first appeared. At once he realized that the unrecognizable, towering mass was what had been steadily working to pull him in the entire time, and there was the certain acknowledgment that he was about to be consumed. The vaporous, incorporeal wall loomed before him, and he was dwarfed in its vast silhouette. Like a particle of matter swept into a vortex he slipped into its magnetic field, and the next instant, before another thought could form in his mind, he had collided with it. There was an initial resistance after the impact, and then he was swept up in its current of rumbling energy and carried through it, fast enough to where he felt the intrinsic bonds of his own being begin to pull apart, out of and yet into the unknown. And the darkness there was so great that it seemed to shadow his very soul.
When at last he swam back to consciousness, he found that he had been, mysteriously, left standing on a stable surface. As his eyes adjusted to the new location he realized he could see to a certain extent, and was able to make out thick walls of a silicon substance on either side of him. But it was a moving wall, and its currents cascaded slowly in an eternal rhythm. Ah. He must have reached the main parsing tunnel: a slender passageway that led through the Dangai and connected the World of the Living to the Soul Society. For the first time, hope stirred within him. His emotions and thoughts had returned and was himself once again. Having somehow managed to come this far, he sensed that escape was now close at hand.
When had he first begun to feel trapped? He had wandered through the oblivion behind the wall many, many times. He knew that the Dangai was dangerous, and it had always remained a mystery to him, but never before had he felt the overwhelming threat that, at any moment, he would slip through folds of time itself and be erased; forever and immutably.
Lost in deep pondering, he did not sense the ground shaking beneath him until a sudden light flooded the tunnel. It shone so brightly that it pierced straight through him and, turning slowly, he found himself facing a much more eminent threat. His eyes widened, and without another second of hesitation he turned on his heel and sprinted in the opposite direction.
“Tch,” he clicked through gritted teeth. Such an inconvenience. What he could not understand was, ever since a harrowing run-in with the Cleaner some decades before, he had implanted a specific sensor in his body that should have stalled the progression of the Kōtotsu. But for some reason it had malfunctioned, which both perplexed and frustrated him. Not to mention it seemed an incredible act of misfortune that his arrival in the passageway should just so happen to coincide with the day that the Kōtotsu ran its course. After giving it some thought, however, he decided that it was most likely due to the energy created in the wake of the Cleaner’s movement that he had been able to find his way here at all, which presented two questions: The first being how he had managed to pass through supposedly impassable layers of time without a conscious effort or awareness of doing so, and the second was how long he had truly been gone. Or rather, how much time had passed him by. A week? A month? A year?
More concerning was the Cleaner that crashed through the tunnel behind him, edging nearer and nearer. It still seemed impossible for him to externalize any amount of energy, but he found that by deliberating his movements he was able to slide forwards through space, as if travelling through a dream. It was a residual effect of the Dangai, he had concluded, as if an aura from the void was still clinging to him.
But still he was not convinced.
Soon the air became choked with the dust that was pushed up by the sweeping momentum of the Kōtotsu. He frantically searched the path before him for any sign of the light that would lead to safety. But there was only darkness. The Cleaner continued to barrel along its course, and he increased his speed. Perhaps if he could use Hohō… It was worth a try, at any rate.
He focused his Reiryoku, waited for it to culminate, and then took one step forwards.
It felt as though his mind had been split sharply in two, although the pain was more psychological than physical, and when his wavering vision had cleared he saw that he had jumped an indiscriminant distance ahead of the Kōtotsu. It was like he had moved with Shunpo, but it was obviously not Shunpo. More like a projection of his being to match where he had been looking at just a moment before: as though he had moved with sheer force of will alone.
But he was not left with much time to ponder the anomaly as, just then, a gap appeared in the blank space before him. It was the opening that led to the Senkaimon. He did not know what would happen as soon as he passed through to the world outside, and could only hope that whatever metaphysical abnormalities had been affecting him would be stripped away as soon as he left the Dangai. Still, considering the ever-encroaching Kōtotsu, it was not as if there were any other options available to him. And so, with the adrenaline that came from fear pulsing through his core, he dived into the light.
There was one, harrowing moment where the fringe of darkness rushed up behind him, as if it would latch on to him and drag him back into the abyss. He was left bereft of all his senses, and in the void that remained in the wake of erasure even knowing itself fell away from him.
And, for a fraction of an instant, he was nothing.