So to set the tone and setting for this one-shot please see below. (If not please proceed on with the story.) This is straight from my Tumblr account so please excuse the...very rough wording.

Let's pretend even after drinking Shizuka's blood via Kaname, Zero isn't totally free from that downward spiral into the crazy. (That point is actually a little unclear in canon. Like, is he, or is he not?)

And Zero, after having consumed a lot of what might as well be the elixir of life, is taking a god awful long time to get there (which he is very aggravated by).

(He was ready to die before a normal human lifespan — frustrating as fuck, but fine, there's no changing that. Now? He's practically lived for two lifetimes, and it's not like any of it was fun and games. He wants to get a move on.)

So by now, he's pretty old. On the inside. On the outside, he still gets asked for ID in a liquor store.

Cross, too, is even older, and hasn't changed appearance-wise at all. Stuck in that almost middle-aged, but not really phase.

Both of them try not to think very hard about it.

. . .

The Way You Move

. . .

"Do you know how those kids see you? They would worship the ground you walked on if you let them."

Zero sent Cross a look that very clearly said, "And I will never."

Cross continued as if he saw nothing. "They're still in that admiring stage, just like their parents were, before they developed a good sense of self-preservation and learned to be scared instead."

It was what happened nearly every time. Because if Zero had been fairly competent at keeping people away when he was an actual teenager, now, with so many years of practice under his belt, he was a total pro. No one could tell what the hell he was thinking.

Bad for teamwork? Understatement. But in Zero's case, his strength was the equivalent to roughly a thousand regular hunters, he had no problems going solo on missions. And coming back without a scratch or even a facial expression to mar his usually blank countenance.

"The HA has been steadily gaining a mafia impression, and half of it is probably you." Cross whined.

What with nearly every hunter calling Zero 'sir!' on some kind of instinctive auto-pilot, it was no wonder. It had been hilarious, at first, and Cross had put in his fair share of teasing, but now that he thought about it, he should have put a stop to it before it had become 'the unspoken rule'.

Now, getting everyone to change 'the unspoken rule' was going to be a bitch and then some.

Where was Yagari when he needed him?

Oh right, six feet under.

As well as Kaito.

Not for the first time, Cross was vaguely mortified to remember he was currently the only hunter who knew Zero when he was still a child. And human.

Dear god, he was too old for this.

But he wouldn't have anyone but Zero take after him, and Zero, the stubborn boy, still hadn't come around.

Retirement was so gloriously far, he could cry.

"Please Zero. Just one session. There are some things only you can teach." Cross begged. Catching Zero's expression, Cross smiled wryly. "No, this is not a pseudo therapy class, you don't need to talk about your manpain. I said teach, not threaten or traumatize.

"Just tell them about your more unique missions. What most hunters don't experience, but the kids might still need to know if they do. Not every one of them is going to end up on stand-by or enforcement duty. Some of them will sign up for the front lines, to go face to face with violent vampires, both crazy and not, and there are some things they need to know.

"Please?" Cross added again, just for good measure.

After a few moments, Zero offered a slight nod and walked out.

Cross sighed in relief and took off his glasses to unnecessarily clean the lens.

Christ, getting Zero to do anything he wasn't comfortable with took an effort and a half, but he almost always complied, still, when appealing to his softer need-to-protect-the-innocents side that hadn't managed to wither away during the years.

"I hope those kids know how rare of an opportunity this is." He murmured into his empty office.

. . .

It seemed they did, since once the word got out Zero was to sit in on a session, the class couldn't have filled fast enough.

Zero, the mafia celebrity. Cross felt like laughing again. In hysteria.

. . .

"I won't waste time explaining what you're going to learn in standard hunter training." Zero started out in what was, Cross despaired, an impressive monotone.

He couldn't have sounded less enthusiastic. Thankfully, the kids were too enraptured by Zero being there at all to notice or care.

"I'm only going to stand in for this class. You either get what I'm saying now, or you don't. No questions." His voice turned a little sharper when a few eager hands went up.

The hands immediately went back down like chastised puppies. The rest of the students looked dejected.

Cross wanted to smack his forehead. Then smack Zero upside the head.

Miraculously, Zero ran his eyes once over the large crowd and uncomfortably relented, "But if you really want to ask, go to Cross."

Some of the older hunters who'd come to watch blinked and looked at each other in amazement, though they didn't dare talk aloud.

Hah. No one believed Cross when he said Zero had a soft spot for kids and the untainted. Or anything non-vampire related. Well, here was the very proof of it.

Suck on that, you skeptics.

He refrained from cackling, but it was a close thing.

When everyone turned their heads to look at him in response to Zero's seemingly uncharacteristic kindness, Cross just smiled brightly. "You're free to stop by during office hours. I usually have a gist of Zero's schedule and will let you know when he's free." His glasses glinted. "You all know where he lives, right?"

The students either nodded or answered in the affirmative. Zero's brow twitched.

He leveled a glare at Cross, but continued, "Some of you are curious about vampires. Don't be. You ensure they're keeping to the code or you kill them. Your only advantages are your instincts as a hunter and the ability to wield an anti-vampire weapon. Get attached to what you kill for a living and you lose both of those advantages.

"The reason you can't trust vampires," Zero's eyes narrowed, "is because they're exactly like us. They think of themselves first, their benefits, but while most humans stick to hunting other species for safety and survival, most vampires stick to humans.

"Some will say vampires always have an agenda, they're ambitious, they can't care less about anyone but themselves. The same can be said for humans. The difference is that vampires are higher up on the food chain. Given the choice between animal blood and yours," Zero emphasized, "they will, without doubt, choose yours."

Despite his monotone, every student was looking up at him, none were talking, wondering when this was going to end.

"When seeing a human wanting to be bitten, leave them to their mistakes. Nothing you say will change their minds. There are no words to describe the role a level D plays within vampire society for someone who has never known or seen it firsthand. Even less for level E vampires.

"Get too invested in wanting to play savior and all you will do is breed resentment in addition to losing your only advantages. You'll know what I'm talking about when you see a familiar name and face on the elimination roster."

The older hunters nodded solemnly, a few with empathic pained grimaces.

"It doesn't matter who it turns out to be, family, friend, lover, you'll see their name and you won't be able to kill them. But you won't be able to leave it to someone else to finish the job either.

"You'll be a hunter with a failed assignment. And you'll leave other defenseless humans vulnerable to the vampire you failed to kill."

Cross, too, nodded in agreement, heart heavy. This needed a little uplifting. Pulling a piece of blank paper out of nowhere, he tugged a pen from his hair and quickly scribbled out,

"TALK ABOUT THAT TIME WITH THE LV B WHO THOUGHT SHE COULD FLIRT HER WAY OUT OF TROUBLE!"

Zero's jaw spasmed, just a fraction, but it was enough to get Cross to smile.

The students looked wide-eyed and half traumatized.

Cross could see the moment Zero gave in.

"When not engaged in direct combat with a vampire, you will sometimes get sent on useless assignments just to give useless warnings for those in violation of less significant rules."

This time, Cross' brow twitched.

"Some vampires will comply, some will pretend to comply and do it again, some will think it a joke, and some will use it as an opportunity to get a hunter in their pocket via disgusting flirtation.

"You are free to kill them if the last option happens."

A few students' jaws dropped.

Cross frowned mightily and crossed his arms in mighty disproval.

"Or," Zero's lids lowered in exasperation, "you can aim for their kneecaps." His voice was still at a deadening monotone. "That will be enough of a deterrent. Usually. If the kneecaps don't work, or you can't reach them for whatever reason, aim for their face. They will immediately step back to protect their only profitable investment."

The students blinked. Most looked blank.

"Should neither of those work, they are obviously broken, lacking severely in self-preservation and you can kill them, because they won't have a long life expectancy anyhow."

'What.' Cross mouthed. And when he saw some veteran hunters actually nod in agreement, he mouthed it again, 'WHAT?'

"Gender doesn't matter. Apply the same method for either male or female. It will be equally effective." Zero said it with the confidence of personal experience.

Wait, wait, wait. Cross only knew about the one incident with the lady level B. Had there been others? Had gentlemen level Bs tried to hit on Zero? And Cross never knew?

Turning the piece of paper around, he wrote:

"WE ARE GOING TO TALK ABOUT THIS."

Then, taking a fresh piece out, he wrote:

"MENTION THAT TIME YOU HAD TO GO UNDERCOVER."

Zero just raised a brow.

"THE ONE WITH CROSS DRESSING STRIPPER VAMPIRES."

"There are times when going undercover is necessary for an investigation," Zero started dutifully. "Avoid it at all costs if possible. If not, you're fucked."

There was a smattering of muffled laughter from the hunters.

"Should you be placed undercover in a stripper club as a client, don't act as a sexually frustrated human waiting for gratification. Vampires can sometimes smell lies like days old garbage. The ones who can't are living on borrowed time. You can kill them.

"Be upfront on why you're there. Vampires don't like hunters, they hate hunters who waffle. They also hate hunters who babble. In most cases, they don't want unnecessary trouble and will cooperate to get hunters out of their hair faster. If they have to sell out a coworker, so be it. Vampire strip clubs are never out of strippers."

There were always more replacements.

"If you're dealing with a vampire who has a measure of influence, they are even more inclined to stay out of trouble. Because in those cases, trouble with hunters will equal trouble with the Council. And having to deal with the Council is as much of a pain in the ass for them as it is for hunters."

A few of the students choked on what sounded suspiciously like laughter.

And the hunters were now practically looking at Zero in a completely different light.

Like, 'Wow, he might be a vampire, but that doesn't mean he has to go through less shit than we do. He can shoot faster, last longer out in the field, and has literally killer instincts, but he's still part of the HA. Actually, he must have done some seriously embarrassing shit in the name of the job.'

Not even Cross had heard Zero speak this much at once. Getting Zero to do this was pure genius. He was a genius, yup.

"If a vampire refuses to cooperate for whatever reason, apply the same method in the case of flirtation."

Cross blanched even as he vehemently shook his head. The students didn't need to learn about torture and interrogation yet.

This time, Zero was being willfully blind to his gestures.

"Go for the kneecaps. That will give you enough time to incapacitate them. Use the spare knife you should be keeping on you at all times to carve into their face. Make sure to mention it also contains anti-vampire properties and will hurt like a bitch on top of not healing smoothly."

There were at least four blood-thirsty students who were avidly taking notes mentally if not in actual notebooks.

Cross wanted to cry.

He still wrote out:

"LESS LIKE MAFIA, REMEMBER."

Zero seemed to give that a bit of thought before saying, "If that's not a preferred method, you can also use the anti-vampire handcuffs issued to you to bring them in to HQ for official questioning."

Cross nodded gratefully. And then wrote out:

"YOU CAN WRAP UP NOW."

"Make sure you know what your reasons for being a hunter are. Reaffirm them as often as you can. Despite what we do, most of us aren't vampire killers. A majority of you will be similar to human law enforcement."

One brave little girl held up her hand and asked, "Are you like the police?"

Hushed silence.

Blinking slowly, Zero softly said, "No."

The girl nodded like she already knew what Zero was going to say. "Then I'm going to be like you. If that makes me a vampire killer, so be it." She said, echoing Zero's words. "I'm real good with my aim and I'm real fast. I can go for the kneecaps just like that. And I'll protect the humans."

Other students, encouraged by the girl's outburst, all murmured in agreement. Cross could vaguely hear, "Protect the humans, yeah."

And much to Cross' horror, Zero went a little soft around the eyes and even twitched his lips in the barest glimmer of smile before nodding approvingly, like a proud teacher.

The students promptly went starry eyed. The bright glint in them were not unlike the ones belonging to a fanatical cult following.

Dear god. What had he done.

. . .

A/N: The numbers for Zero's strength is pretty much influenced from Shingeki no Kyojin, where Rivaille, a thirty-something year old man, is currently the 'strongest man alive' and is roughly the equivalent to 4000 soldiers in skill, experience, and technical ability.