You people already know my opinion on the Persona series and MHA so let's go forward!
FFNet. Summary: Izuku Midoriya thought he was down on his luck the day he was convicted of a crime for trying to save someone. As if being Quirkless wasn't enough, how he was supposed to be a Hero with a criminal record? As it turned out, fate had another plan for him.
So basically the Persona series happened in the world of MHA but also in the very same Persona-verse. Because the Persona-verse goes space-time continuum level of madness.
While there are certain canon divergences (Shiho staying and the Illegals' activity), it's still P5. Major events will still happen.
Barring the Kaneshiro incident probably since, in the MHA-verse, the yakuza are gone. Literally with Chisaki's arrest. Maybe Chisaki or a Hero would up being one of the major targets instead of on the ranks of Madarame and Shido.
While the P5 calendar of events has to stay in a strict schedule from the targets to the social link to the Christmas Eve Apocalypse, I don't know what the Illegals and the MHA would do.
Additionally, by the story's end, please add the Shadow Operatives. The Shadow Operatives could be a Hero Agency but a strange hero agency at that since they picked those who only have not quirks but rather have a Persona. And they combat the supernatural when others like All Might and Eraserhead could not. Think of them more underground than even the underground heroes and villains like Eraserhead. And they don't even score on the board or anything. Every one of their workers has a day-job but has so much experience in fighting Shadows and the supernatural that it's a given they are far more likely to take on gods than All Might. And they are saving the world far more frequently than these heroes just fighting criminals who used their powers for the wrong reason.
Listen, Nyarlathotep could and will destroy everything All For One worked for in a second. I know it because I saw how he is during his appearance. Messing with All for One's mind would be so easy for him.
Well, Izuku...Be glad that you are part of Persona 5 than any other Persona flagship titles.
If you were in the original Persona, you will fight against the Snow Queen AKA Nyx and temporarily Nyarlathotep with Kandori. You were stuck basically in one city because it was cut off and new heroes could not come in to save.
Because if you were in Persona 2, you will fail to save the Earth from Nyarlathotep. Because you aren't part of the adult team that did save the Earth from being destroyed...
Onto Persona 3, you would save the Earth certainly but at the cost of your own life. The thing about P3 was accepting one's death while living life to its fullest extent. I'm sure you don't mind sacrificing your life to save the world and acted as the barrier between Nyx and Erebus but goddamn it's playing right into your self-destructive habit of saving people at the cost of yourself. Minato/Makoto knows this and did it too but never at self-destruction. Izuku must learn self-preservation, not to kill himself for the greater good which would go against the theme of P3. He must live while accepting death. His acceptance of death is not like Akinari or Shinjiro or Ken or the rest of SEES.
While Persona 4's protagonist survived, he's in high school. UA is a high school and I don't think Yasogami High has a hero course. I don't think Gekkoukan High has a hero course, no matter how rich it is. In fact, I don't see any Persona-user in any of the flagship titles choosing to become public heroes when they had other interests. It's not that they aren't heroic but because it's simply isn't them. They are good and moral people certainly and had standards. They would save people, regardless of one's history and will treat people with human decency. You might be saving the town from a serial killer and later the world from a god but I doubt you would want to stay like this. They had dreams and hopes that they can achieve on their own merits.
Besides, Persona-users are different from Quirk-users, mainly that it's not a power that anyone can get like candy. You quite literally had to be broken to have potential - the more visible the mask, the visible the persona. A persona is a mask to protect yourself. To be an actual Persona-user, you have to accept the darkness in your heart and have your power that darkness instead of the darkness powering you. Additionally, Quirks have a limit, Personas don't. Sure they had a limit on the stresses of your mind - SP/HP but they are easily revivable with items and spells while you basically had to wait out until everything's in order because Quirks are biological functions. I literally fought one boss in P3 for nearly three hours. I was just damn lucky I was efficient with my items and SP. Sure, there is 20% of the population who won't have quirks but if and only if they were broken, then they have potential. There is a major difference between gaining a Quirk and Persona; in one of them, you must literally be broken...while the other is a biological function.
For example, Aoyama would have potential and he would certainly accept his Shadow in one try instead of rejecting it because from what I saw from him, he won't even deny it since he was willing to talk about it to Deku. Normal people like Ojiro and Sero won't have any potential. The entire staff at UA won't have potential, not Aizawa nor Nighteye... Probably Nedzu would have potential but I have serious misgivings about him, namely of his misanthropic behavior and that he could be the traitor if the traitor theory is indeed true. I think All Might would have potential, just by the fact he's wearing a mask. Of Class 1-A, those who have potential will be Aoyama, Kirishima, Deku, Bakugou, MINETA, Asui, Jiro, and Ashido. Probably add Ochako and Iida depending on the masks they wear. Momo, as much as I love her, puts up a mask for some time but I doubt she has potential the same way her supposed love interest Todoroki has - listen, I'm not a TodoMomo shipper in the slightest but ship whatever you want. I'm a happy Tododeku shipper alongside Kacchako since I find that pairing more appealing than IzuOcha. Shinsou will have potential too.
Hell, in DRRR, Izaya and Shizuo would certainly make the shortlist of having potential; I am absolutely certain if I place them in the Persona world, they would undoubtedly have potential. Kadota and Tom will not have potential whereas Simon will. No matter how badass I find you, Dotachin, you would never ever had potential the same way Izaya and Shizuo has.
Izuku, you have no clue what is waiting for you in this world. Considering PQ2, you would be meeting other Persona-users who would use mythological figures from Greek to Japanese to Chinese. You have yet to meet Aigis, a humanoid android capable of emotions. It dropped right into the uncanny valley but she's just as real as Morgana and Teddie. You have no clue you just collided with gods or godlike beings at all, demons certainly, but gods or godlike ones like Igor and the Demiurge. You have no clue about the Great Seal and the multiple apocalypses this world even has. Persona-users are the only type of people who can fight against the godlike beings, not the Heroes. Not even All For One would be able to stand against godlike beings who can quite literally kill him on the spot and I do mean on the spot. Nyarlathotep could manipulate his darker tendencies and unleashed on the world what All For One can do worse than he was usually doing. Nyarlathotep could also kill All For One easily. Philemon can do the same as does Igor. Demiurge could also kill him, Izanami could kill him, Marie could kill him... As gods, they are basically higher than any human, even a human with a longevity Quirk or multiple strong quirks. Nothing could kill them barring the destruction of humanity itself.
Yes, this world has apocalypses in the past...near multiple times for utter destruction but absolutely in one case...where if you were a teen and helping Tatsuya and the gang then...you will fail.
Listen, it's one of the things that make you a Persona-user and stopping an apocalypse at the hands at one of humanity's gods is one of them.
Like for Heroes, you stopping crime, petty or otherwise, although I doubt that they'll be able to stop the crimes that are still there in the real world and would still happen in a world with superheroes. Look at DC/Marvel where corruption amongst the populace and police are still viable.
But the end of the world shit where you have to stop gods from destroying everything. Yeah, Quirks could work but won't make a dent, unlike the Personas where the enemy is more likely to have weaknesses. Quirk-users would tire themselves out.
Let's go onto the world of BNHA.
Hmm... how can I say this? I think to some extent, it's quite dystopic.
For starters, Quirks are raised to a level. Yes, there is good equality for LGBTQ+ individuals - see Tiger of the Wild, Wild Pussycats - but there is the same discrimination. Just look at the bullying at Izuku and the posturing of Bakugou for starters. The Quirkless was bullied for something they can't control and those with 'heroic' quirks are raised up.
Not to mention, something that would fit right in with P5: the Hero industry. There are people who undoubtedly are not heroic by any means, taking it as a job than an act of heroism or using it for other means. Think the Heroes as...not as pros but rather as an auxiliary police force.
Even if Endeavor is not one of the Phantom Thieves of Heart's targets, then a Hero should be one. Since the Yakuza is all but gone in the series, then the Phantom Thieves' target instead of Kaneshiro could be a Hero.
Analyze the Hero Industry. If in the story there are corrupt cops, then they'll be corrupt heroes all the same. The canon of MHA practically had corrupt heroes and treated the job as a job.
Just because they are working against villains does not mean they are good people. The Phantom Thieves had their flaws but like the rest of the Persona-users, they are good people.
Hell, analyze the industry. Crossovers like the CCS crossover and Conversations with a Cryptid did it.
Now consider UA: it's basically a military school. While police schools are self-contained and they don't go to war against people who can bloody kill them in an instant... I don't think a majority had a license for teaching. Some of them can be good teachers like Aizawa and Midnight...but at the same time, they are moreover soldiers going to war against an invisible enemy.
Yes, there will be people who used their Quirks in criminal activity. I am not even going to talk about the League of Villains nor Chisaki in any form in this since it's pretty obvious.
I want to think about the pro Hero industry as an auxiliary force like I seriously wanted to. All Might helped stopping everything he sees including a robbery. However, these Heroes don't seem to know what is there to take about the know-how of policemen, particularly Japanese police.
The Japanese police force has lessons on how to interact which the pro Hero industry clearly did not demonstrate well in that regard. Some might be good with kids - All Might - but others not so much. They can take what it means to be on the field of pro Heroism but in terms of how the Japanese police do their work, they don't know shit.
The Japanese police learned theory lessons. From what we saw from UA, there are normal classes on top of training such as heightening their Quirk's limit/exposure. No lessons on interactions with victims or other necessary lessons that other take. I'm pretty sure they had Hero-related projects in the classes but something like teaching students to calm victims - something that apparently they had to know instinctively - is something that never appeared as appropriate classes. In comparison, Koro-sensei's classroom seemed downright normal because at least he only made sure they were trained in the arts of assassination for his murder and nobody else. Sure they can now defend themselves which is great. But he never wants them to use their new skills for anything but his murder. Nagisa even went on to teach with the sheer exception of his murder.
Sure, UA is teaching these Heroes about their powers but do we see theory classes on how to treat children or victims? Somehow, it must innate for them to even learn the dang thing. Saving them from a dangerous situation is one thing but it's another to reassure them without making them panic. Having kids learning to rescue traumatized victims from their horrible situations - I seriously wonder if I can pretend to merge any of the SMT worlds with MHA so I can see just how ineffective the whole Hero industry is when it comes to the apocalypse - and expecting them to already know. Deku literally had to learn on the job. Sure he and Togata are great with kids but he nor Togata are truly equipped to even go about a police operation that required superhuman powers to combat, not children.
These UA Heroes think they can sniff the traitor in their midst. Listen, just because they are Heroes does not mean they have the skills equipped for that level of investigation. Get the Japanese Special Defense - until it is a national threat, use something like the police force to sniff it out. Even the Persona series does this because the supernatural stuff is usually in that area and does not require national attention particularly for what looks like murder or rumors becoming reality or what just looked like people admitting crimes. Just look at Detective Conan where the Special Defense and the FBI are digging up dirt for the BO. I would totally understand the supernatural stuff where the police nor the nation realized what is happening. But when there is something like a traitor, don't get Heroes, get agents to infiltrate with the necessary skills. I'm more likely to trust Detective Conan's FBI/CIA/JSD over the Heroes any time of the day.
The over-reliance on overpowered spectacular Quirks is also a problem. Now it's probably Aizawa was in the same place as Hitoshi Shinsou and the probable cause of having a new test in mind of different Quirks.
Heroes are raised to another status altogether. Sure they are some good ones with All Might being worshipped for his genuine human decency but there are others who just had the quota.
Now MHA is all about what makes a hero.
I just don't trust the Hero industry in MHA. Yes, there are good heroes who deserve praise for common human decency like All Might but there are others who are not Endeavor or Captain Celebrity. I'm far more willing to trust the vigilantes in MHA than I will the Heroes.