Dreams of Armageddon [Kimetsu No Yaiba/PROTOTYPE] One shot

[ScriptGenius12]

I've been thinking about whether or not to turn this into a full story, and while I have several ideas, the main ones regarding the backstory are below:

Spoiler

One thing to consider is that the BSL was one ingredient out of multiple in Muzan's medicine. An important ingredient, but not the only one.

Those other components would likely need to be found before any demonization could occur, but given Mercer's sheer skill and Gentek's* massive resources, it may still be possible without those other ingredients if effective enough substitutes can be created or found.

The main impetus for this snip was the idea of what a "Modern" strain of the demon disease would be like. If a doctor during the Heian period managed to figure most of it out by himself, what would it be like if a modern medical corporation with large resources and comparatively smaller moral compass tried their hand at making it? How different would the demonization effect be? Would the resulting infected have any resemblance to Muzan's brood? The same weaknesses? None? New ones?

Creating a mood of tension and dread was a major direction. A sense of ambiguity was also built up through what was left unsaid.

How did Gentek first learn about the BSL? Just how much do they, and by proxy Mercer, know about what it can potentially do?

Do they know about demons? Do they know about Muzan? About the Demon Slayers? If so, how?

There is also the Demon Slayers themselves. A new generation is taking up their swords and cause. Will this incarnation consist of the characters we saw in the epilogue, or an entirely new cast with sufficient motivation to get involved? A mix new and old characters?

Note that while the narration mentions a "Rising Sun", there are many places where the sun rises above the land. This new generation of slayers does not necessarily have to solely hail from Japan.

Finally, I think I will only keep this as a one-shot for the foreseeable future. I haven't made a solid outline for what would happen after the Penn Station incident, assuming that the event and everything that occurred before it would still happen exactly as it did in the game. I am working on other major projects, including my ongoing fics and some RL duties.

There is also the fact the idea is on some level a cruel twist ending to the epilogue.

Fanfiction is not meant to follow the stations of canon to the core, and deviation is a big point to much of it. Acts of cruelty happen often in the native stories of both sides of the crossover, with the deaths of good people being as common as the victories over literal monsters.

Nevertheless, I feel that a full continuation would go against the spirit of the manga's ending, about how the descendants of the original cast get to live in peace after everything that their ancestors went through.**

Now they live in a time where demons are set to return in a far more dangerous "modern" form in a highly populated city. The "Masquerade" as it was will not last long.

And that's before we involve the assorted horrors of the Protoverse.

These events may be occurring a continent away, but the fact of it still remains.

In one way or another, some of these descendants are likely going to get into an extremely dangerous conflict involving old foes in new forms and new threats with more than a few similarities to the enemies of their ancestors.

The question is how it will happen, and if it can make a good story without the sacrifices of the Kamado siblings and their allies being rendered futile in hindsight.

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*Also Blackwatch by proxy.

**The battles against and the final death of Muzan come to mind. There is also the fact that the survivors of the final battle and any immediate children that had would have likely end up living through World War II. Even if they probably lived away from the cities that were attacked during the war and understandably weren't likely to want to get involved with any of it, this is still something to consider.