Unexpected letters aren't a good sign. They're a very bad sign when you've spent the last year learning about spies and assassins and all the ways they work.

Izuku might be a little paranoid, but quite frankly he, and every underground hero, has every right to be.

Even when they're wrong and everything is fine.

Okay, I know I said we'd move into Izuku's high school life next with a new fic, but this needed to be dealt with or it would be very clunky later.

That said: I am not off hiatus. There are still some things I need to deal with and clean up (or write entirely) before I am comfortable posting, and life has been... yeah. On the other hand, I'm really close to being ready! I just have no idea when I'll actually be able to work on it! So... hopefully soon!

This is just after Izuku sends back his decisions, but before the school year actually starts.

People didn't send things by snail mail these days. Or, they did but only for very specific reasons. Mostly bills and paperwork—things where people still insisted on a physical copy—or packages being shipped from who knows where, plus a few other odds and ends like acceptance and rejection letters. Even adds and junk mail didn't come in physical form anymore. It was all digitized in emails or pop ups or things like that.

But this letter was not a bill. It wasn't a legal document, or a formal notice. Izuku would know. If it was anything like that, it either wouldn't be his name on the letter, or it wouldn't have come through the mail like this. Karasuma-sensei and the Ministry of Defense would never risk anyone even seeing any official correspondence between them and Izuku.

Which brings Izuku back to the letter at hand. These days, when you got a letter that wasn't a bill or paperwork, it was either a prank (or scam, or other ill-intended trick), or someone trying to avoid leaving any kind of electronic trail. Neither of which were particularly good signs. As a result, there were a number of steps people took to avoid making fools of themselves, and to get back at anyone foolish enough not to cover themselves.

Step 1: Check the return address. See if you know where it's from, if it even goes anywhere. There are some people that find the feel of sending a letter more intimate than other options. This, of course, is no guarantee that the return address is accurate, but it's a starting place, and if it goes nowhere (or doesn't have one), that is a red flag.

Step 2: Was it sent through the postal service, or delivered by hand? If delivered by hand, proceed with caution, and probably call the police.

Step 3: Open the letter and find out what's going on.

Steps 1 and 2 are mostly just so you know how much to prepare for. Some people chose to throw out the letter unopened if the return address is faked, but no one throws out something with no address. If it's a threat, you will want some evidence.

Izuku, of course, did his due diligence. So he knew that this letter (supposedly) came from Sir Nighteye's agency offices and was delivered through the official postal service. He had even taken the extra steps of checking weight, and balance, and holding it up to the light to see the there was anything in there other than a letter. It didn't feel like it, but the paper stock used for the envelope was too thick to see through, so his last test didn't really help any.

With nothing else to do, he opened the envelope. And got a letter. Just a letter. Which is good, because Izuku didn't know whether or not he needed to be concerned about poison.

Midoriya Izuku

Okay, starting reasonable enough.

When you are done with this letter, burn it as soon as possible.

A bit more concerning. Actually, a lot more concerning.

Several members of the underground hero community have expressed interest in mentoring you as you work to join our ranks, but have also been understandably concerned about such contact being used against you or against us, should the information fall into the wrong hands. Given my knowledge of your performance at the Toku entrance exam, I agree with these sentiments and have volunteered to initiate contact between us.

What follows are instructions for access to a secure group messaging server and the rules thereof. There is also a list of members and what they are using as their call sign.

With interest

Sir Nighteye

That was… interesting. Checking the following pages, Izuku found the instructions, rules, and a very long list of names and code names. Okay, it was all code names, but it was their official hero names and the new name that definitely looked like it belonged in a standard internet chatroom.

Izuku brushed aside the new information and went back to scrutinizing the letter's authenticity. It was handwritten and appeared to have been signed by Sir Nighteye personally, though that didn't actually prove anything. It was very easy to get samples of pro heroes' handwriting. The information also didn't provide much to go off of, given how little Izuku knew about underground heroes. Even for all his research, they were called underground for a reason.

And if they were talking about him, that just provided a convenient excuse if someone had overheard them and was now using the information to mess with him.

The rules also made sense. No using real names or hero names. No discussing work directly. No discussing classified information. Only certain people had the ability to change anyone's names (which prevented any confusion over who was who by requiring it to be planned and announced, prevented people from sneaking in, and was aimed at preventing people from hacking the server to change their names).

All in all, it was a very convincing letter, but not one that was beyond question. And Izuku was not about to trust like that. Not after an entire year of learning how to lure people away. How to tail, track, trick, and kill.

Maybe he was paranoid, but he wasn't going to just ignore what he knew. Someone could have faked this. Izuku himself could have faked this, if he wanted to. If he ever decided he needed to.

Hell, even the names on the list. He didn't recognize most of them, but the ones he did were definitely in the right line of work.

He saw names of people who simply avoided the media like the plague despite being well suited to the spotlight with Koujin, Phantom, and the legendary Seamstress he only heard whispers of.

He saw those that were primarily informants, or had quirks others distrusted, like with Rhapsody, The Count, and Sir Nighteye himself (though All Might's former sidekick was far more trusted and public than either of the others). And The Count's presence explained how anyone knew about his test results.

There were the ones that were too grumpy to be popular and too willing to get their hands dirty to be mainstream, like Mora.

And there was one that stood out. In all Izuku's research they were little more than a whisper in the back streets of Korusanto, and those whispers all thought of Legionnaire as a vigilante being protected and hidden by the civilians just as much as she protected them. They didn't call her a hero.

That last bit was going to push it either way. Either this was actually from the underground and they knew things Izuku didn't, or this was a cleaver trick that had pulled some vigilante names to pad the number.

Really, there was only one way Izuku could know, but the concerns brought up about villains knowing the connection and using it were valid. He couldn't just be out right about it.

Even as Izuku pulled up his email and opened a fresh draft addressed to Sir Nighteye, he knew he had to be careful. In the subject line, he wrote "The Letter." And in the body, he simply put:

Confirm or deny.

Midoriya Izuku

Two days later, Izuku received a response. By then Izuku had recorded the names, rules, and instructions in an encoded journal and destroyed the original letter. (The base of the code he had learned alongside Nagisa-kun from Karasuma-sensei in the name of keeping their notes and plans secret from Korosensei. Izuku had later modified it, so that even they couldn't read his notes. A necessity with all of Izuku's secrets.)

The response was only one word.

Confirm

Little bit of extra detail on future plans. The sequel has a name now! It will be Keep Moving. Again, hopefully soon, but I'm not sure exactly how long this will take.