Discussion Blood Demon Techniques, the Method and Madness

[Admiral Teach]

Discuss the aspects of the demon's signature power system here. (Please beware of spoilers while discussing. I will do my level best to keep this first post free of them to keep the hype-train going. Pun not intended, mostly.)

This thread is primarily here to help figure out if there truly is reason behind the maddening array of blessings Muzan's blood grants upon its partakers, and to organize it into a coherent power system.

So, I had a brief discussion, part argument and part comparison of personal tastes, with @Jammin in the anime thread. He made some interesting points regarding the fights and the demon blood powers. At first, I disagreed with him, but later it struck me that he had a very good point: there does not at first glance appear to be reason or hard rules behind the Demon Blood Techniques. And that is an acceptable literary technique to keep the power mysterious. However, it is good literary practice to keep such powers within a consistent contextual framework.

That means our glorious Gater-sensei has duh rules. But she isn't sharing them. (Well, Nezuko rewrote them, and we all know she isn't one to talk much, so there's no helping it.)

On what basis does the blood grant such staggering abilities?

How do they work, exactly?

What really are they doing?

Is there even a limitation on what kind of powers can be formed?

And what even is Muzan, that those who possess his blood can spring forth dimensions, swim through swamps of darkness, weave increasingly complex webs, etc.

At least a few of these questions I had sort-of subconsciously assumed or answered in my head to my personal satisfaction. Perhaps they aren't quite so concrete outside my head, though.

My initial thought was that the demons were just plain supernatural beings and could just... do stuff. Then, as the fights drew on, particularly versus the Upper Moons, a pattern began to grow clearer that now in hindsight was always there.

First, the opposing power mechanic, Breaths, appears to be much simpler and straight-forward magical in aspect. But are the demons?

The means of how their powers work literally is in the name. In almost all instances I can think of at any given time, the powers of the demons can be explained or directly derive from manipulating their biology to staggering levels in one way or other. Each Demon blood Technique derives its function from a bodily process and connects directly to demon blood, and the amount of purity of that blood (the closer it is to Muzan's) the more powerful the BDT, as well as control over the demon's own biology.

Therefore, Blood Demon Art has the following primary elements and the demons that acquire strong BDTs have the chemstry to mix them right:

1) Biological Self-control
2) Blood Purity
3) Human Blood Quantity
4) Evolution
5) Reproduction/extension

(Will post more later when I have the time, going through each oni and how their powers use these 5 principles. May remove a couple that don't fit...)

 

[Gladiolus]

I was re-reading the fight with Hantengu, and after analyzing a bit his Demon Blood Art, then came to my mind: it could be that he had a dissociative identity disorder, thus explaining why his ability consisted in splitting his body into stronger ones, each one representing an aspect of his psyche? I re-read his dying thoughts, and when he was accused of his crimes, he claimed that it was the fault of his hands, and that he was innocent, so maybe he had a split personality: one being his usual his cowardly one, and the other being murderous and cruel.

I know maybe I'm thinking too much into it, giving that Hantengu was supposed to be a cowardly scumbag, but I thought it was an interesting theory.

 

[kkck]

To me demon blood techniques appear to be one of the most generic aspects of KnY so I've never really given them that much thought. And even within the context of the series the focus was never on specific abilities but rather the demon's character development. I daresay the author probably put more thought into how demon blood techniques related to the specific demon (as in basic skills or backstory) or how it affected the plot rather than in its actual mechanics.

While the author never explained demon blood techniques he also never did anything with them that had us go "huh?". In general it sort of made sense that demons with seemingly magical abilities could be defeated by the main gang or the hashira. We also never had a situation with a demon having such an impossibly powerful ability that the only way to defeat it was via another impossibly powerful ability from the hashira. Which makes sense because the hashira did not have the skillset to counter impossibly powerful and plausibly magical abilities. All they had was their breaths which increased their physical capacity and chunks of metal they wacked demons with. The closest thing impossibly powerful abilities was good old muzan, who was defeated mostly by tamayo and her biological warfare rather than the hashira and the metal sticks they swung around. I suppose yorichi was strong enough to take on the impossibly powerful muzan but it is worth noting that even he was not in any way, shape or form magical but rather he was just a strong guy who was good with a sword.

 

[HereNThere]

I'd say Blood Demon Arts followed the same rule of cool that Bleach followed. Basically, what kkck said. The actual mechanics of the ability aren't as important as to how they further explore the demons personality.

In one of the volume extras, it was flat out explained that Akaza's abilities are all based on aspects of his past. What his ability actually did was never really explained.

It's also quite lucky that the majority of the weaker demons had the more complex Blood Art abilities while the stronger demons had more straight forward techniques.

What if Muzan had Gyokko's ability? With his strength and speed, everyone would be fishes.
What if Kokushibu had Gyotaro and Daki's ability? Not only would everyone be poisoned, their first go at decapitating him would have failed if he had a second demon inside of him.

 

[kkck]

I'd say Blood Demon Arts followed the same rule of cool that Bleach followed. Basically, what kkck said. The actual mechanics of the ability aren't as important as to how they further explore the demons personality.

In one of the volume extras, it was flat out explained that Akaza's abilities are all based on aspects of his past. What his ability actually did was never really explained.

It's also quite lucky that the majority of the weaker demons had the more complex Blood Art abilities while the stronger demons had more straight forward techniques.

What if Muzan had Gyokko's ability? With his strength and speed, everyone would be fishes.
What if Kokushibu had Gyotaro and Daki's ability? Not only would everyone be poisoned, their first go at decapitating him would have failed if he had a second demon inside of him.

IIRC gyutaro's and daki's blood demon art was to manipulate a scarf and flesh poisoned sickles. I am not sure the two being the same demon is their demon blood art. But you aren't wrong about such a thing making kokushibo nearly invincible...Though kokushibo's actual demon blood art is somewhat similar to gyuko's (bone sword vs flesh sickles). I am also not necessarily sure that lower demons necessarily had stronger blood demon arts. Sure, kokushibo's was definitely weak but akaza's seemed strong enough for his rank even if we don't know what it is. Doma's was simple in a way but its applications nearly endless... Nakime had quite the blood demon art but unfortunately the skill wasn't meant for combat at all. Hatengu's ability was nothing but straightforward... He weaponized a split personality disorder as far as I can tell. And gyoko's ability was also nothing but straightforward.