The Mechanism of Kafka's Transformation and How It Affects Him
(Crossposting my analysis/theory from Reddit. Also, warning: this post contains both anime and manga spoilers so beware if you are anime-only)
So, something that drove me nuts about the manga's version of the X-ray scene was the fact that there was literally no difference from a normal human chest x-ray. The anime THANK GOODNESS fixed that:
We finally know exactly how Kafka's core looks while he's in human form. It appears to be primarily occupying where the chambers would be with a good amount of myocardium (the heart muscles) suspending it while also continuing to function as a heart.
Notably for me, there's actually a translucent hemicircle up top there where it's supposed to connect to the aorta. In fact, you can see the core is translucent on its left (our right) side while more opaque to its right (our left).
Let me highlight it for reference I hope y'all appreciate the fact I had to do it with a mouse on MSPaint because Reddit won't save images to drafts and I can't drop images from tablet like on desktop:
It appears that Kafka's heart was fully converted and the tissue there is just a facsimile since it appears to be forming a pouch for the core to nestle in.
The anime's expansion of the scene the Mysterious Larva/Young Yoju fused with Kafka ended up perfectly tying in to this. Something I noticed was that Kafka was not actually transforming for most of it. Initially he was clutching at his throat where it entered:
Then just before the transformation started (when his eyes started glowing), he was clawing desperately at his chest:
For reference to anyone who's never studied anatomy, the mid-esophagus is actually resting against the heart, which is why the best form of imaging for the heart is a transesophageal echocardiogram (i.e. stick an ultrasound down the esophagus), which works like in this diagram:
In other words, the Larva's target was his heart and it was burrowing into it from that point. Which is consistent with where Kafka was clawing at in the shot I posted before and why after the change completed, his hand was resting just above that area:
Basically, the theory I have been saving specifically for after this episode is: Everything about Kafka's body is tied to the core.
Yes, that was obvious since we saw him regenerate his entire body from just the core, but what I'm saying here is that that the heart was the only thing the Larva was trying to fuse with. The rest of the body followed instantaneously once the heart became a core. Kaiju cores appear to be storing a lot of energy, so it would fit in with why even the initial change could happen so rapidly. It was a large burst of energy that had Kafka's cells all convert and restructure, and we even see steam coming both off and out of him here in the anime.
All future changes seem to be purely a matter of him controlling every cell in his body like individual muscles or even like how cuttlefish and octopi are able to change their appearance in an instant from muscle contractions and chromatophores.
In other words, the evidence has stacked to full OVERKILL that Kafka is truly a kaiju that can shapeshift into a human rather than the reverse like he and everyone else prefers to think.
Which leads me to my big pet theory right now: the reason Kafka is losing his ability to revert to human form is because he's becoming malnourished. I won't stack the image evidence since I've already done enough and the focus is on the core and Kafka's real biological nature now (I'll save that for a future post, lol), but it only stands to reason that if Kafka is physiologically a kaiju regardless of form, that means he has the metabolic needs of a kaiju.
He was only fine before because he had a lot of extra body fat as reserves and didn't use his kaiju form much. But after entering the Defense Force, he's been in multiple situations where he had to push himself while transformed and consume much more energy. If you pay attention to his body type, you'll notice he's been having quite a bit of weight loss.
Sure, he's been training a lot too and eating better, but following the fight with Isao, he's becoming abnormally thin. Maybe not enough for people to immediately think he needs a sandwich, but as of the latest chapters, I've noticed he's actually pretty lanky now even in kaiju form when previously Kaiju No. 8 was built like a bear.
You could argue it's just art evolution EXCEPT literally no one else had such a drastic change in body type or AT ALL. I'm pretty convinced this is an intentional transition from Matsumoto.
Whatever Kafka is eating as a human, it's not enough to sustain him long term and so his body is going into power save mode. And since his default is kaiju (why else would he constantly slip up his first few months if it wasn't actually his default form?), his body is losing its ability to shapeshift because it doesn't have the energy to. Malnourishment tends to manifest in a similarly piecemeal fashion irl, so I'm not surprised its first sign is just one spot on his hand.
Such a deceptively simple reason for the kaijufication is precisely why I'm very certain that is the cause. Kafka has a lot of issues with loving and taking care of himself. And this series is all about subverting tropes in favor of common sense. It's not some "inner demon" trying to take over (the Larva actually only did that once because Kafka was both in danger and refusing to fight back what it perceived as another daikaiju); Kafka just isn't taking care of himself as usual!
And there you have it, folks. Finally, a clear breakdown of what exactly the Larva did, how the transformations work, and why the kaijufication may not be as scary as everyone thinks. Or rather....not in the way they think. Someone please feed that kaiju properly!
