#jjk worldbuilding

[hollow-lime-green]

hi hana!! so i’ve been obsessed w this since string theory: can you tell us a little bit more about your interpretation of the six eyes? i know it’s said that satoru can see in thermal and infrared, is there anything else he can see?

Oh yeah! This is a fun question! I just got stuck in traffic for an hour (as a passenger), so I am going to over-explain this. And I'm bored so I'm going to highlight it with pretty colors like I'm writing in my diary or something.

Satoru's senses basically span the ✨entire energy spectrum✨, because the Six Eyes gives him the ability to work with all types of energy. He can see the EM spectrum (infrared, visible light, and ultraviolet), he can see thermal energy, he can sense (not exactly see) some other types of energy (electrical, sound, chemical), and he can see cursed energy like we do as JJK readers (plus some extra details like the taste, color, and texture of cursed energy).

I'm about to be insufferably STEM, so more under the cut:

Electromagnetic (EM) Spectrum

The EM spectrum has infrared light at low frequencies/high wavelengths, the visible light spectrum, and then UV at high frequencies/low wavelengths. Satoru is kind of like a mantis shrimp in that he sees way more colors than a human. He's got more rods and cones and stuff. (I like physics and chemistry, don't press me on the biology).

I don't really go into the UV part that much, but I like to think that would contribute to his sunlight sensitivity! He's not an outside pet.

The blindfold blocks out the EM spectrum because the fabric blocks the transmission of visible light in the form of photons, packets of light energy. (this is a secret tool that will help us later)

Electrical Energy

I haven't really gone into electrical much either, but like he can see the flow of cursed energy, he'd be able to sense the flow of electrical energy, i.e. the movement of electrons. It gives him good circuit sense.

Sound Energy

Sound energy is vibrations* (another tool that will help us later). He doesn't really see them per se, because even the thought of him actually seeing the vibrations in the air is overwhelming, and it would block his vision so much that I don't think it makes sense for the Six Eyes

I think he would feel them with the Six Eyes kind of like a gentle breeze. It makes him ultra perceptive, but it's still another form of feedback for him to deal with.

This is why I make Satoru so terrible with enclosed spaces. If you can see those forms of energy, you're seeing not only the original instance where they're emitted, but also every secondary instance when things reflect or refract. So sound bouncing around in a train, for instance, is completely overwhelming to the Six Eyes if he's not able to use jujutsu to filter it, which I think is a skill he wouldn't master until maybe his mid 20s.

Thermal Energy

Now this is the fun one.

The Six Eyes gives Satoru the ability to see and sense the energy in things in its various forms, because he can convert it all to cursed energy, or back. So, when you think of thermal energy, you probably think of thermal cameras, which represent thermal energy in the color spectrum, which kind of looks like light.

But thermal energy is very much not light - it's actually motion. Specifically, it is atomic vibrations. The more energy something has, the more it vibrates, and that is actually the basis for what we call 'heat' or 'temperature'.

If you go deep into the philosophy of temperature, it's all a sham. It's the way we choose to interpret and understand a phenomenon we can't really see (atomic vibration) translated into something we can measure (but our scales are all relative and kind of fake. I'm looking at you, Rankine!). But that's a conversation for my very Serbian thermodynamics professor. Existential doubt really flows better in a Slavic accent.

Anyway, remember photons? Okay, so, heat and sound are not light, right, they are vibration. So instead of quantifying them as light packets, we quantify them as vibration packets, which are called phonons. I reference phonons a lot in the fic, but probably not in a way where I have appreciably explained anything about them well to non-STEM girlies.

If you think about photons/photon emission as throwing a ball of magical light at something, you can think of phonons as throwing a slinky at someone. (Which I wouldn't recommend, actually. Slinkies are remarkably difficult to throw.)

Cursed Energy

Okay this one is a gimme but obviously I have to list it. In the JJK animanga, we the reader see the cursed energy auras/flames around people, but it's understood that those are not actually seen in-universe, at least for non-Six Eyes. It's kind of dumb, but it also kind of makes sense pragmatically. If all sorcerers could see cursed energy, then it really ruins surprise elements, residual coverup, and general battle mechanics. Of course, some sorcerers are known to cover up their cursed energy, but if all of the powerful baddies did that then it wouldn't look as cool. It's whatever.

Also, the whole 'training to suppress your cursed energy release' is a hard sell if we also say that literally any sorcerer can see CE. So this is why Suguru isn't aware of when he's leaking CE. He can't see it, and then he also can't really taste/smell it because people go noseblind to their own scent.

In FIYM, Satoru is the only one that can see see it. The rest of them can still sense it, but they sense it by smell, taste, and most importantly, vibes.

Thesis: Why Energy is Gay

Okay so yes I did this to answer the question "what does Satoru see through the blindfold". But I also did this to make it gay gay homosexual. (In the grand tradition of JJK)

Touch Sensitivity

Because Satoru is sensitive to kinetic energy, living things are incredibly potent to him from a sensory perspective. People are made of energy - particularly thermal energy, chemical energy (although this is potential energy which we haven't touched on but I do reference it here and there), sound, and, of course, cursed energy.

When Satoru touches people, he feels all of the vibrational energy from those kinetic energy sources as well as the cursed energy, which to him has textures on top of the vibes, colors, and smell/taste. So of course it's overwhelming. Every touch is combined with vibration, which is very gay, and would take a long time to get used to, even if he never formed the habit of using Infinity to cut himself off from the world.

In FIYM, it's not only a fear/safety/vulnerability thing, it's also a necessary filtration step that he uses for the world. Part of this is because I kept him in Kyoto/the clan setting in his backstory for a long time, so he would have had less sound and population density to deal with. Tokyo would have been super overwhelming for him.

Information Filtering

Speaking of filtering, there are two ways for Satoru to cut down on the amount of information his senses are getting.

One is to block them, which is what he does with the blindfold (blocks photons) and Infinity (blocks phonons). Gay, tsundere, and hot.

The other is to flood or mask his senses, which is what happens when Suguru infuses the blindfold with cursed energy. It's not that Satoru can't see anything, it's that all he can see is the cursed energy, and it blocks out his ability to sense anything else because of how strong and close it is. This is meant to be a direct analog to the phenomenon of detector/sensor saturation, which is to say that a detector has hit its limit of how much it can read/measure/detect, and so everything else is lost.

When Suguru flares his cursed energy, he's doing a baby version of that. He's flooding Satoru's detector (The Six Eyes) with his cursed energy (which is easy on the eyes, for Satoru) and that inhibits his ability to sense the other pesky things. And it makes him feel better.

Physics is gay, physics can be so gay. Greg's biggest sin was not capitalizing on how gay the physics can be. Any day now we'll get an announcement for his next project, a gloomy isekai titled: Transported To a Dark Academia Yaoi Battle School And I Fall For My Physics Tutor?

Anyway, I hope you enjoyed the over-explanation, thank you for the ask, I love getting the chance to ramble about some of the science. :)

[loonela]

Jujutsu 119 - sorcerer hotline

Japan's IRL version of a national emergency hotline is 119, where they can call for police, fire, and EMS. It makes sense for Jujutsu society to have one for jujutsu related activities. They use the number 422 for all calls, but like a call forwarding machine, will send you to one of three lines depending on your report. Ieiri Risako, Shoko's grandmother, founded the system based on her time in the United States and their 911 nationwide system. To call the number, a sorcerer or window must have a phone with a registered cursed energy signal, or use a special cursed energy token with a landline.

422-1: Mid-mission support. Backup requests, extractions, and EMS are sent through this line.

422-2: Curse and mission reports and updates. This line is called by windows or sorcerers surveilling new curses or sorcerers upon completing missions. This line is not fully set up in 2005.

422-3: Casualty reports, of both non-sorcerers and sorcerers. This line is also used for breaches of secrecy, damage control, and property destruction.

Jujutsu 119 encompasses the whole system, but responders to any call act out of 422-1. All members carry pagers and mobile phones for alerts. Depending on each sorcerer, one may receive some combination of backup, medical, or extraction alerts.

Regular sorcerers may find themselves with a dispatch from Jujutsu 119 due to backup or extraction requests. One example is Gojo's canonical overseas mission to rescue a Grade 1 sorcerer in the curse womb arc.

[sukunasthightattoos]

okay do you know what the jjk high schools are missing? i need a cursed tools workshop and either an archive or record keeping department. i want curse research. i want jujutsu history. i wanna see people wrangling curses to shove em into tools. i want more worldbuilding and lore expansion and fuck i now have an OC idea.

OC and their family who specialize in the creation of cursed tools. but maybe they're not a respected family exactly? more like... they're important, but they're in service of/indebted to the big three families. they've got a family technique that allows them to imbue curses into the tools? i gotta think some more about it

[marichild]

to moving forward

It’s all Gojo’s fault that Megumi’s birthdays are so special to him, in the end. He’s not sure if that’s exactly a good development.

Birthdays can mean more than one thing.

🪐 2.1k || rated T || itafushikugi || gojo & megumi & tsumiki

🪐 post-canon || hurt/comfort || bittersweet

🪐 inspired by THIS AMAZING ART by @hinamie !! I hope you enjoy this hina and I am SO sorry this took forever </3

[vikcacao]

Doodles bc I'm thinking about the itafushi demon&angel au fic I'm writing lol

And now I'm gonna rant about my ideas bc this is my blog, and I'm having fun writing this fic, and if I don't talk about my thoughts somewhere I will expode

Hell is a cave, why? Because I, the artist/author, am terrified of spelunking. I think it's one of the worst ways to die, I hate it so much. And Hell is typically below Earth, so a cave would make sense then, too. But mainly because I'm scared of caves (that is also Megumi is the first drawing lol)

These are also the youngest versions of these guys I've drawn so far. Gumi doesn't have his face scars, and Yuuji doesn't either (only his cheek is fucked up, but that heals eventually). They're both very, VERY, young in terms of demon/angel aging. They're like 15/16 human years, and angels reach their first stage of maturity at 100ish years old

This will be on ao3 eventually, there's probably only gonna be a few chapters. The first chapter is not even close to being done yet, but it does have LOTS of notes lol, so it will be finished eventually :]

[duckiemimi]

apparently the jjk we know now was not the jjk gege had in mind before chapter 1, and this...this makes a lot of sense actually (context: here, and also this is one of the first drafts).

[curiostars]

Wow I don’t have a caption for this one. Something something Yuji Itadori. This quote is from The Magnus Archives podcast.

(w/o words under the cut)

[eternalera]

okay but like. i kinda love how in jjk you literally cant become a sorcerer without questioning every aspect of your reason to be one as 'protecting the weak' just isn't enough. because why are you protecting them? why are you willing to die so young to protect people who you dont even know and will never know? whats wrong with letting the curses kill them? sure you have the power to stop it but anyone can become a police officer and catch criminals and they dont fill guilt when someone random gets killed.

the concept of protecting the weak works for law enforcement in the terms of wanting to do good for others but not for sorcerers because of a simple reason.

theyre creating their own problems, why should i have to fix it for them? let alone risk my own life for them?

its unfair, especially when the non-sorcerers aren't always gonna be the kindest towards sorcerers. sorcerers have to deal with the pain that comes from the people that they protect and yeah, it fucking sucks. which is why protecting the weak isn't a good enough reason.

its not your problem. its theirs. so why become a sorcerer? lets look at a few.

Mei Mei is obviously in it for the money

Megumi is only a sorcerer to protect him and his step sister so that they can support each other and live

Gojo wants to change the sorcerer society because he doesnt like the way thats its ran, constantly taking stuff from the youth (i mean technically he was most likely forced to but this is the main reason that he stayed in it as hes the strongest so like... who's gonna say 'no you gotta stay' to him right?)

Yuuji feels like consuming Sukuna is something only he can do so it makes him special, so fuck it. why not?

Nobara just wanted to live in Tokyo.

Now i'm not saying that all of these mean that they don't want to protect others, but thats not their motivation for becoming a sorcerer. while with Geto its pretty clear (from my pov) that he only wanted to become a sorcerer to help the weak.

but while he got born with a strong cursed technique it has a downside... it kinda sucks. it sucks in the form of he's consuming everyones emotions and taking on their burden for them in a much more twisted and literal sense.

he literally embodies the struggles of a sorcerer in a sense and yeah. it breaks him because he's doing it for the weak right? but with every curse that he swallows it gets harder and harder because which each curse he wants to stop. he wants to quit being a sorcerer because of this burden being too great and his reason not being strong enough to carry it as its completely selfless.

he gets practically nothing out of protecting them besides a horrendous taste in his mouth and some cash which isn't the reason why he's doing this in the first place.

im gonna stop it there because its getting more into a geto analysis not but you get the point-

imma do one of those later. BYYEEEE!!

[girl-of-ink]

Once again thinking abt the secret good version of jjk where junpei lives

[hollow-lime-green]

we were talking about the Naoya incident in fiym comments and I had this thought: Hana, what happens when a sorcerer dies of natural causes? no cursed energy involved, just organ failure. I'm thinking about what the implications are for sorcerers growing old

You know, this is a super interesting question that also doesn't come up because we never really see sorcerers die peacefully. I think the only one we see is Old Zen'in (forgetting the name rn) which kick starts the Naoya/Megumi heir conflict. And since it happens off screen, given everything, we can't technically confirm that he died of old age lol.

But I think going with what we know in canon, it would depend on how they felt at the end of their life, and if they had unfinished business. Unresolved tension and negativity would lead to elevated CE, and I think that could be a good metric for the likelihood that they would turn into a vengeful cursed spirit.

A sorcerer that feels closure would probably be able to move on peacefully, since even though jujutsu isn't ending their life, they wouldn't have a tether to keep them going and give them purpose as a cursed spirit. But, as we hear from Yaga, no sorcerer ever dies satisfied. :)

I went back to reread 193, part of Naoya's transformation fight. I was surprised to reread and remember that he really does keep his intelligence and ego as a VCS. That doesn't necessarily conflict with other worldbuilding, but I think it would be more interesting if they reverted to a more curse-like level of intelligence and brutality, then could slowly learn and grow back to their human level.

[longagoitwastuesday]

Kusakabe, dear, you're too beautiful to be saying that kind of stuff

[beastenraged]

Sometimes I need a reminder that the vast majority of people don't casually implement the ancient Egyptian idea of a soul being divided into different parts for their worldbuilding/headcanoning.

Because I'll be reading someone like JJK Mahito bragging about how they're affecting something people claim is so precious, being the soul, and I find myself wondering, "Okay Mahito, so what? Are you just fucking around with people's life force part? That's not going to affect anything truly important, as humans consider it."

The entire conversation between Kenjaku and Mahito about if the soul affects the body or vice versa was me going, "You guys just affect different parts of the soul. Duh."

[marichild]

if it shines here

“Oi, you’re gonna break your glasses,” Suguru says, walking over carefully and plucking his dark frames right off his face. Satoru frowns up at him. “Don’t get all pouty crybaby on me. You’re the one who ditched us on your birthday.”

“It’s my birthday,” Satoru retorts, sitting up straighter, looking the other way, and immediately regretting it because Shoko stares down at him with an unimpressed stare. Ugh. His friends are so nosy sometimes. “I can choose however I want to spend it.”

or: Satoru, sixteenth birthdays, and best friends who keep him tethered.

🪐 1.2k || rated G || satosugu || sashisu-centric

🪐 bittersweet vibes || emotional hurt/comfort

[weakinthekneez]

i feel like the opposite of what happened to the jjk storyline is happening to bsd

[curiostars]

Hi guys read my jjk fic it’s good I promise. nothing bad ever happens to Tsumiki and Megumi I promise :)

(also try zooming in and out on the art >:] )

[kakapim]

I swear Who Would Win mindset completely ruined any Shonen anime discussions. As a Bleach fan who watched JJK recently I thought more people would've made silly crossovers like. Urahara and Gojo being friends but nope 99% of it is nerds fighting eachother on who beats who like GIRL I DONT CAARE give me your fucking headcanons instead