Having a quirk that gave you the ability to break each idea you're introduced to by every possible factor was both a blessing and a curse.
Nezu knew and understood this fact very well.
It was why his relationships generally were difficult to maintain outside of a business sense, because often the best course of action for him wasn't the one that would make him friends.
Which was sad but frankly very necessary, even now after many years of work and a reputation as a hero he was in a precarious position as someone that wasn't human.
Nezu had made a lot of political plays to even get where he was now, first by playing as an innocent child the commission could use as Mascot hero then making himself out to be a hyper-intelligent mastermind no one could touch.
But at the same time he couldn't be seen as that threatening or he'd give the commission reason to remove him from the power he needed to keep himself safe as a person.
And for the first time he could possibly remember Nezu had met someone that was in a position similar to his own, though with noticeable differences.
Yes, Izuku was a human whereas he was an animal.
But when one looked at the current laws it was clear to see that a two-toes had less rights than some protected animals.
And Izuku, unlike himself, had many people in his corner, especially compared to himself.
However, most of Izuku's people weren't anymore his friends than Nezu's students were, even if Izuku had a closer relationship with his students.
But that was where the differences ended as far as he was concerned.
As both Nezu and Izuku had to face multiple people wanting to, for lack of a better word, dehumanize them for what they were born being.
Some of those threats being serious enough to be life-threatening.
That their respective reputations were the only thing that kept them each in a somewhat safe place for them.
Places that they could be easily taken from by one wrong move and thrown directly into the wolf's den.
And it was this last fact that had Nezu ruminating for the past couple of days.
Because his last conversation with Izuku had him pondering.
Mainly about Izuku's plan and by taking it apart at every angle to dissect it, and unfortunately, Nezu could only find that Izuku's comment about it being their best option was only becoming more and more true.
They had no choice but to kill All For One, locking him up would only be a temporary fix, if even that so killing him was the only way to permanently be rid of him, something he knew needed to happen since the man had no qualms about using others as cattle.
And that most plans wouldn't be viable because of the numerous quirks he held, poison immunity could be built up without a quirk and centuries of time to do it, and as Nezu ran through the other options only bought up dozens of counters both aided and without help from a quirk.
The only way to kill All For one would be by doing something that the man couldn't anticipate, like using a 'loyal' Nomu to kill him with a gun at point blank range would indeed be the only way to do it without escalating to a full-on war that would kill thousands, if not leave the entire island completely desolate for who knows how long.
Of course, just one shot wouldn't be enough but it would give them the opening they needed while the man's brain was half destroyed to ensure he could not come back, even if he found a healing quirk that would let him survive severe brain trauma.
And Kurogiri, quite frankly, was key to this plan working as teleport quirks weren't common and All For One would be on alert for any foreign ones, Kurogiri's would on the other hand be unsuspicious and give them the split second to take the first shot.
Kurogiri was basically a unicorn in a pre-quirk world for them.
Izuku's plan, on top of minimizing casualties to single digit numbers, would safely get the most at-risk victims safely away from All For One.
However, despite knowing this was the best plan, Nezu couldn't help a welling sense of unease with it.
Because the entire plan hinged on Izuku, a person who he was quickly realizing that he was becoming very attached to, staying in an incredibly dangerous position and staying deep in enemy territory.
And there was absolutely nothing he could do about it.
Tenko was attached to Izuku and it would be near impossible for them to organically make another relationship even half as strong, Izuku had found lightning in a bottle and they wouldn't be able to remake it so Izuku was the only person who could keep an eye on what was going on inside All For One's circles.
Something they undoubtedly needed but Nezu couldn't find his usual comfort from these facts.
Nezu wished that he could give Izuku just one person he could rely on while Izuku was doing this but there wasn't anyone they could send in that wouldn't screw everything up and lose it all.
The few people in the know would frankly react far too much and try to overcorrect the situation with a few key exceptions but those people still wouldn't be able to add much more than their two cents to the situation at hand.
Nezu's ears drooped and he climbed up onto his desk so that he could be within arm's reach of the gash Izuku put in his desk.
Two weeks, in not even two full weeks Izuku had taken over a place in his life that would be completely impossible for anyone else to ever replace.
Who else would he talk with fully assured that the other person wouldn't look at him as less than or that he was only a mammal-like parrot?
Nezu didn't even need a quirk to know the answer.
No one would.
Not his students he taught himself, not the people he had worked with for fifteen years, not even Aizawa who hid in his office and who saw him as an equal and respected him as a person would be able to fully separate him from the fact he was an animal and connect with him on the same level Izuku had.
This line of thought bought him to let out a sad series of chuffs.
Nezu had always wondered if his emotions and instincts could overcome his quirk and while his passing affection for the students he took under his wing was a sign, it wasn't enough and could just be happenstance.
The urge to protect the young was the strongest out there and no creature on earth didn't have it and regularly overcame the insurmountable instinct to protect yourself.
But Izuku wasn't one of his students, yes, he was young, but Izuku wasn't a child in his eyes so this desire to protect the boy didn't stem from that instinct.
If anything, Nezu saw Izuku as a packmate, despite the fact that Stoats like himself didn't live in packs, or groups of any kind.
Reeling himself in, Nezu took a deep breath then returned to his chair and wrote a text to Izuku asking him if he could possibly meet up with him today, and apologizing for asking this on a Sunday since he knew that Izuku spent the day at home with his mother.
His texts had been left unread for most of the day, something he understood and Nezu resigned himself to having the conversation tomorrow instead and went back to his work, mainly so he could have more time to speak with Izuku the next day.
But when the sun set he got a reply from Izuku, one asking if he'd mind Kurogiri portal him straight over to his office, Nezu quickly answered that it was absolutely fine and gave the coordinates for his office.
Seconds later a portal opened up in his office and Izuku entered in a set of pajamas "Apologizes Nezu, however I doubt this will be a quick meeting and I don't want my mom to know about this, so I hope you can forgive my state of dress." Izuku said as he sat down.
"It's fine Izuku." Nezu assured, quickly racing over to the other couch and sat across from the boy.
"So you wanted to discuss the All For One situation further?" Izuku inquired and Nezu chirped with agreement.
"Yes, I understand that there isn't much I can do to help you with your plans but I could do this." Nezu said placing a few documents on the table.
Izuku raised an eyebrow but took them and began reading them only to pause as he looked puzzled and Nezu took it upon himself to explain it.
"It's a deep cover civilian contract. Occasionally, the loved ones of villains and other criminals will come to a hero offering information, this is a contract that will grant them immunity to gather more information and aid the case, even if it means to do some illegal acts." Nezu told him.
It wouldn't be surprising if Izuku didn't know about it since contracts like this weren't used often and the few who were willing to go undercover were sent to witness protection after their time undercover was up.
"If you sign this contract with me, I can give you a blanket of safety when this whole situation comes to light and keep them from arresting you as you were working under my direction in order to take down a dangerous villain, even if that means you must use lethal force." Nezu further added.
Izuku remained silent as he kept reading, likely to double check the wording was correct, he wasn't offended since he himself had painstakingly went over each word and the laws that applied so that Izuku would have full protection.
After a few minutes Izuku took out a pen and he signed the place where he was supposed to on the contract before he passed it back to him "Thank you Nezu." Izuku muttered.
"Of course Izuku, you are taking a big risk for all of us, the least we could do is make sure you don't burn for it." Nezu responded and signed the contract as well, fully understanding that Izuku had given him a great deal of trust by signing this contract.
Because Izuku was essentially trusting that he wasn't going to screw him later and that Nezu would be going to face the consequences of Izuku's actions.
"On another note, would you be willing to meet with those involved with the current holder of Inheritance? I understand this must be kept from spreading to many people but I think we should at least inform them of the current situation." Nezu questioned.
Izuku frowned at that and leaned back crossing his arms "I don't know." Izuku replied clearly very hesitant about this, not that Nezu could blame him.
"If you don't want me to then I will accept that and not say anything to them, it will cause problems but ensuring your safety is far more important." Nezu assured with a series of chirps.
Izuku leaned forward and sighed, one hand covering his eyes.
"... Who all is involved?" Izuku asked.
"I'm sure you know the current holder is All Might, his former side-kick Sir Nighteye was made aware due to his quirk, Detective Tsukauchi is also aware of this because of his quirk, Recovery Girl, and the only other person is the friend of the previous holder and All Might's mentor a retired hero Gran Torino." Nezu listed off.
Izuku hummed "I see, I already knew that Tsukauchi would know given his connection to All Might but I would like to take some time to think about bringing them into the fold." Izuku answered.
Nezu chirped "That's all I ask Izuku." Nezu said "That should be all we need to discuss, thank you for coming to meet me today Izuku." Nezu told him.
Izuku nodded before texting someone, likely Kurogiri since the portal opened after a few more seconds and Izuku left.
Nezu turned his gaze back to the contract and went on to put it in his personal safe after making five plus copies so that he could hide the other ones in case the original was somehow 'destroyed' by 'accident'.
It is a personal headcanon of mine that anyone with a brain that works like a supercomputer or superspeed to the level of DC comics line of Flashs processes their emotions faster than the average person.