I carry many keys, but only one held any importance to me then. It was to an empty cell. Deep below the Imperial Palace, there is a terrible place, and it is there I keep my vigil. Within endless tracks of silent caverns and warded chambers lie things that are too dangerous to roam free but are too valuable or too difficult to destroy. We are the only ones who could stand watch over these terrors, entities and artefacts, the very knowledge of which would drive mortals insane. But for centuries, I guarded them, Warden of many charges, and not once had any cell been breached.

Until that day. That yawning door to an empty chamber, a darker spot in the deepest dark, shouted one word to me: failure. 

Failure. For ten thousand years, we have lived with the stain of it. One purpose, one reason to exist, and when He fell, so did we. This knowledge is a weight we can never shed, and yet, it drives us forward and makes us stronger, for we cannot afford to fail again.

An empty cell, a lock sprung open, a horrifically successful experiment from the Dark Age unleashed. I couldn’t explain how it happened, and it didn’t matter. I could not allow it to stand; this failure, at least, could be undone. So I hunted.

Mile after silent mile, I ran tirelessly. Signs of my quarry were subtle and few, but I found them: sections of tunnels which turned off in a different direction than they had a decade before, a slight disruption in gravity, an hour spent travelling in a single direction only to find myself back where I started. I was not lost – I cannot become lost – the fabric of space itself was rebelling against the thing that had slithered through it. And I would find it, no matter that it hid from me in its folded corners of reality. There is no rest, only the vigil. Only ensuring that the locks stay shut.

I found what was left of the bodies on the third day. To keep our charges contained, psychic wards and runes of entrapment are inscribed into the floors, walls, and gates. But these wards must be tended. So potent are the evils kept here their psychic pressure erodes the runes like an oily sea beating against the rocks. We do not possess any psychic ability; that weakness has been carefully pruned from our ranks. Instead, we must trust the maintenance of these wards to others.

I knelt amidst the carnage and read the story of their deaths in the twisted angle of a cold limb, the stuttering pattern of sprayed viscera. The wounds were distinctive: flesh turned in on itself, corpses fused to each other or the floor or the ceiling. Sometimes, all three. My fugitive had been here, and its victims had died messily, but they should not have died at all. There should have been one of us as guide and guard, and one of us should have been enough. And yet, I read no sign that one of my brothers engaged the threat.

When I picked up the trail again, I saw why: there were now many trails. My quarry made a mockery of the laws of physics. This is why it was entombed here. It could be in two places at once or wrench one place into two. Given enough time to roam free, it could gnaw the threads of spacetime to tatters. My brother was probably still out there, chasing an impossible ghost after one step took him miles away from his now-dead charges.

I smiled, though: the monster could not face one of us; it could only run. And I would always follow. I had one thing my brother did not: I had the Key to this thing’s prison. More than a mere tool to open a door, like the others I carry, it is the lynchpin in the arcane mechanisms that bind the things here, tuned to the unique resonance of its captive. It led me when the path ahead splintered into a nested labyrinth of night. It would sniff out the true path from the phantoms the fleeing abomination flung around itself if I merely quieted my doubts and listened.

I learned its tricks. The violations of space began to take on a pattern, which I read as surely as sword strokes, and I cornered it in its own maze. A slavering monstrosity, hunched, grey skin shifting and bulging to contain a form that could not exist in a mere three dimensions. It was hard to even know how to look at it.

 The key sang as I held it up. ‘This is your destiny, abomination,’ I said. ‘I won’t kill you; that release is forever denied you. I will drag you screaming back to your cage.’

There was no question of its coming quietly. 

Through the trackless night, we fought. Its claws boiled the raw stuff of reality around me as my weapon cut through one fractalising form after another. It was everywhere and nowhere, I was a spot of light the dark itself tried to consume.

In the end, my spear broken, I used my hands. A messy way to fight, but fists sheathed in auramite can break the most dangerous foe if they have conviction behind them. During the march back to its cell, it tried to escape many times, but I had a hold on it now. I would not let it go again. The turn of the key and echoing clicks of eldritch mechanisms locking tight sang to me of small redemption. 

If only it were so easy to seal away all our mistakes.

In the silence after, I could think only of the dark that stretched on and the horrors that lurked there. As above, so below: so many lights gone out.

There is only the vigil now, our eternal penance: ensuring the locks stay shut.