And here we are, onto the next arc: Team-Up!

Meanwhile, in U.A.'s new grounds, that being a repurposed academy that was once called Exegol Academy, Aizawa has just returned from Tartarus, and reports everything that he has witnessed and seen to Nezu and his fellow teachers, including how Spider-Man has suddenly been promoted to the status of a pro hero. This shocks the teachers, and Aizawa reveals further that Spider-Man has been made into an agent of Adriana's new replacement for the HPSC, that being S.I.L.K., and Nezu is forced to tell Aizawa to back off from him and his allies, much to his chagrin. If Spider-Man truly is now an agent of S.I.L.K., then that means that, for now, he is under Adriana's protection, and is now virtually untouchable. For now, they will need to simply bide their time and wait for Adriana to make the first move.

Aizawa would be angered by this, not finding it logical or rational at all, and would increase the training of his students even more to adjust to these new changes, hoping that when the time came to take down Spider-Man for his crimes, they would be ready and able to fight. This would only further the divide between himself and his students, and between the students themselves, but Aizawa wouldn't care for this. They were here to train as heroes, not make friends. They didn't have the luxury of playing nice. Not after the War of the Symbiotes and the subsequent rise in vigilantism, not since Kraven and the fall of the HPSC, not since his own students were attacked by the League of Villains and Sinister Six time after time again. Not anymore.

(This is one of the downsides of Peter Parker's arrival into the world of MHA, as his many threats has followed with him, and has only increased the dangers that the heroes will face, leading to many blaming him for all their new problems and seeking to prepare themselves for those same threats, no matter how they must go about them.)

During this time, Aizawa would begin training Shinso as his personal student, teaching the brainwasher all that he knows about how to fight and operate as an underground hero, but not holding back on him and delivering onto him takedown after takedown in order to train him, viewing the idea of holding his hand and slowing down to no longer be an action that he can take, as to do so would be to disregard threats such as the Symbiotes and the Sinister Six and all of Spider-Man's other foes, and Spider-Man himself, would be illogical and irrational. Shinso would take on this training regularly, eager to prove himself to his new teacher. However, Shinso himself would begin to hide some of his problems and issues from Aizawa, much like his remaining students in Class 1-A, which Aizawa would notice and take issue with.

But, he didn't have time to think about those, as he would be tasked with helping in the investigation of multiple homeless people first going missing, only for some of them to then returning to their usual positions and haunts and randomly attacking people, somehow lost in a mindless rage. Aizawa would set out to pose as a homeless person (others would joke that it's not too far from his actual appearance, much to his annoyance) in order to find those who have disappeared and figure out why many of them are returning back violently.

However, during this time, Aizawa would end up running into Kaine Parker, whom is operating under the moniker of the Other, and his Enforcer crew, who are investigating rumours of someone running about, using some sort of mind control to coerce people to their side. Realising that their missions may intersect more than they enjoy, the two parties agree to work together, for a time, to understand what is happening.

Soon enough, they would track down the culprit behind all the disappearances and violent homeless attacks, and it would be revealed that the culprit was a woman by the moniker of Beros, as well as her minion by the name of Leviathan. As it turns out, the two of them were former minions of a terrorist cult by the name of Humarise, which had been broken up and destroyed years prior, and they were desperately trying to rebuild the organisation from the ground up.

However, recently, Beros had come across a strange gem, one that allowed her to manipulate the minds of others and gain their influence and control.

The Mind Stone, one of the two missing Infinity Stones.

Using this stone, Beros would begin brainwashing and mind controlling various homeless people across Musufatu as a beginning foundation for Humarise's rebirth. However, the process, for her, was imperfect, as whilst some of the people that she'd tried to brainwash did eventually submit to her control, most of them just went mad from it, and ran out to attack people in their new frenzy, hence how Aizawa and Kaine were eventually able to track them down.

Aizawa and Kaine's Enforcers would battle against Beros' brainwashed minions and Leviathan, but during this battle, Beros would end up putting Aizawa under the influence of the Mind Stone, temporarily driving him mad and forcing Kaine to fight him, and then knock him unconscious, freeing Aizawa of the control on his mind, and then, when he wakes up again, Kaine and he defeat Beros, whilst the rest of the Enforcers defeat Leviathan.

But in the aftermath of the fight, Aizawa would turn on the Enforcers, threatening to arrest the villains and vigilantes if they didn't surrender immediately. The Enforcers would move to battle him next, and Aizawa would be angered at the fact that their powers aren't being nullified by his quirk, just like Spot (Shocker, Clash, Boomerang, White Rabbit have abilities born from acrobatics and technological inventions, whilst Kaine's powers are copies and mutations of Peter Parker's, with additional abilities as well), though when they hear the sounds of pro heroes and police approaching, the Enforcers beat a retreat, and Aizawa takes the Mind Stone with him as he leaves.

Soon enough, Aizawa would return to the new U.A. campus, and he would continue to train Shinso in how to become a hero. However, Shinso's silence on his own issues would continue to frustrate Aizawa, as he refused to train Shinso if the boy was too preoccupied with his own problems to give it his all.

And then, in a moment of weakness, he uses the Mind Stone on Shinso, brainwashing the boy into revealing his secrets to Aizawa, and then immediately forgetting what happened.

And Aizawa? Instead of admitting what happened and what he did, he would pretend that nothing happened, and go back to training Shinso, and deciding to keep the strange stone to himself. After all, it still made no sense to him, and he needed to analyse it in order to figure out what quirk made it and how he could understand it.

Plus… it might be useful later on.

It was the most logical and rational decision.

Aizawa's biggest weakness will be his need to judge everything by his own sense of logic and rationality.

His second biggest weakness will be his need to control that which he views as logical and rational.

Both of these will lead him down a dark path...