I love how you write Despair Makoto tbh. I wanna see him interact with the others(maybe even despair Class 77, or V3). Like, what's his dynamic with the class and a few specific individuals? How does he make sure they're still under despair but also around his finger?
(CW: despair-typical self-harming behavior)
With his class, the surface dynamic is a lot of the same behavior we see in Despair's Throbbing Heart, in that he's mostly letting them bully him, mistreat him, kick him around. Especially Sayaka; she's manipulating him, controlling him, making him watch horrific things, and putting him down on the basis of his unremarkability pretty much all the time.
He is not pretending to be hurt by these things; they do hurt. And when he begs them not to kill people, it's 100% genuine.
"Just one," Sayaka wheedles. "Just shoot one, and the rest will live."
"I c-can't," he sobs. "I don't want to. Please..."
But these feelings aren't destroying him in the ways he's allowed them to believe. It's overstimulation, and sometimes he has to shut down so he can keep processing things the way he needs to (Hey, speaking of, someone remind me to think of the protag minigames as a trauma response later.), but overall he's restructured things inside himself so that all his suffering has a place to go.
As long as he knows they hurt themselves by hurting him, it's justified, so he can stand it.
He learns not to mask his emotions anymore. Shaking and crying help to externalize his suffering, which is good for keeping his mind clear and for letting his friends see what they're doing to him and derive despair from that.
What I don't think we directly see happen in Despair's Throbbing Heart (though I'd say it did happen in that continuity as well) is that his despair classmates occasionally get very lucid and apologetic.
It's like I said in Panel of Hope Experts: Despair makes you do the unforgivable, then it makes you self-destruct out of an inability to forgive yourself.
Once Makoto's classmates have burnt themselves out on tormenting him (specifically and especially Sayaka), they'll often find themselves hugging him, babbling apologies.
"I'm sorry, I'm so sorry. You're my friend, I love you..."
How he handles these episodes varies, but overall these moments (when his friends are the most vulnerable) are his biggest opportunities to twist the knife.
Maybe he says something like:
"Can we stop now? My neck still hurts." Quietly, but with the unmistakable subtext of, 'Your theatrics mean nothing to me. I'm still feeling the pain of what you did to me.'
Other times, maybe he'll say:
"Last time, I tried to believe that you wouldn't do it again. Should I bother trying, this time?" Self-explanatory. Comes across as accusatory, but also kind of implicitly gives them an out to be terrible again, because if not even Makoto believes this apology, why should they try to change? It's pointless.
Similarly, sometimes it's:
"You're not fooling me this time," or "Please just stop lying."
Sometimes he just goes limp and silent and lets them apologize and plead with him. This happens especially when they're very clearly looking for feedback of some kind.
"Say something! Anything! Even say that you hate me; I don't care, just say something, please!"
Maybe at the very end he'll say one thing. Maybe a deadpan, "Was that good for you?"
All of it feels, to them, like a window into the deep contempt Makoto must have for them. (Really, Makoto is giving them the suffering they seem to be demanding.)
But basically, crying to him just digs them in deeper, in a way that doesn't strike them as deliberate on his part. It's just the natural consequences of their actions, after all. They don't realize how long and hard Non-Despair Makoto could believe in someone.
With his class specifically, he's overall pretty passive and opportunistic about his despair. It doesn't take much more than just letting them hurt him and a few well-placed comments.
With them, he's more active and direct (but still subtle) about feeding their self-destructive impulses.
When they harm someone else, he might say, "How would you feel if someone [same kind of harm] you?"
And then they're like, "That gives me an idea!" Which leads to them injuring themselves. A few of them start losing fingers, toes, and maybe teeth that way, but more often it's stuff like branding and scars.
Nagito notices, and is fascinated, that Makoto's shut-downs (mind-hiding, or whatever his classmates start to call it) very specifically come out when the others exhibit behaviors like murder and outward emotional honesty, and his more entertaining reactions– his crying and fussing –come out when the others are torturing people, insulting each other, just being generally unpleasant. He notices it because he notices that his class is starting to murder people less and torture people more.
They're adjusting their behavior to do what Makoto subtly rewards.
"You've got your classmates fooled," he observes. "I don't know whether to be disgusted or impressed."
"I think you usually prefer disgust, so I'd go with that one."
"I don't prefer disgust."
"Then be impressed." Makoto smiles, and it's still cute. Still unassuming.
Nagito decides that torture builds character anyway. Really, Makoto is onto something. Maybe he's what the world needs: Less death, more trial. The youth are so wise.
The rest of the class just sees him as their naive kouhai (even though they crave his attention/reactions).
You know, provided he wouldn't be outed to his own classmates by doing so, it's very possible he'd just let their kouhais know that he's despair. Not by directly telling them, and again not at all if it risks making his friends think he's not really suffering when they hurt him, but he doesn't feel he has a particular reason to cover things up about himself, with the 79th class.
After all, they need guidance. Junko is leading them astray.
Shuichi would be so excited to follow Makoto's lead. The main reason Makoto doesn't just become de facto leader of the V3 class is because Junko has some hardcore devotees among them, and he doesn't want them telling her what he's up to, because then his class finds out he's despair and they'd no longer be able to get despair from hurting him, etc.
So he only reveals his actual philosophy to the kouhais he knows care for him more than they do for Junko.
Despair Makoto and Despair Kokichi are actually in a very similar headspace and as such should be kept away from each other at all costs.
Seriously, humanity's priorities in this AU should be:
Make sure Kiibo is still being pacified by Angie.
Make sure Makoto and Kokichi are nowhere near each other.
Seriously, they would complete each other in the most terrifying way. Kokichi's main problem in this AU is that he's just very effectively doing despair and not having any fun. In walks Despair Makoto, and suddenly Despair Kokichi is partnered with someone who is at this point an expert at putting someone in the most satisfying, feedback-looping version of despair they can reach.
It's Kokichi's resources and strategies and drive to take control, with Makoto's sense of justification. They're taking over at least a third of the world. A world of no murder and plenty of harm.
"You have to live to suffer."
Kokichi comes across like the mastermind and leader of the two, but really he's just the method. He takes his agenda pretty much wholesale from Makoto, occasionally complains but very rarely substantially argues. The Ultimate Supreme Leader takes over the world, and the Ultimate Lucky Student is in charge.
That said, Despair Makoto can be reasoned with. He's not doing despair because he organically thinks it's the best thing; he's doing it (for the most part) because everyone has been telling him they want it, ever since the Tragedy. They've made him reorganize his goals and beliefs to align with what they want, as a matter of psychological survival.
If someone were to tell him they don't want despair, it's possible he'd be like, "Okay, we'll make an exception for you. You can go."
But that requires a person to know this about Makoto, and it wouldn't occur to most people.
For most people, the best they think they can hope for is begging the rulers to "end their suffering" or kill them.
"Is that what you want?" Makoto asks.
"Are you sure that's what you want?"
And maybe he gives them what they ask for, or maybe he thinks about it and just says, "There's always a reason to keep living. You just need to find the perfect suffering for you."