Izuku couldn't stop his limbs for shaking in a combination of terror and rage as he watched the vestige of One For All standing there with a grin on his face as he rubbed his chin like he was solving a riddle.

"This is very interesting. I was curious why I couldn't see anything through Lady Nagant clearly anymore. It was as if some fog had obscured her mind, an overwhelming desire that outstripped even my influence. I assumed it had something to do with all the commotion at UA, but I never expected to see you in here" All For One pondered aloud with his sickly sweet voice, leaning into it as much as he could to make Izuku even more uncomfortable.

Izuku just clenched his fists as he stood his ground. Too terrified to attack and too enraged to run away. All he could do was take a defensive stance as his mind worked a mile-a-minute, trying to figure out how All For One was here and what he could do about it.

All For One seamed to pear into the boy's mind though as he predicted what was running though Izuku's head with a grin.

"Come now Deku my boy. I know you're smart enough to know by now that at least remnants of a person's psyche remain with their quirk when it changes hands and even retains a link if they still live. I know I've heard faint echoes of my little brother's voice over the last few years since you inherited One For All" All For One said with something that could have almost passed for fatherly chiding, if not for the clear pleasure he took from tormenting Izuku or the way he said his hero name. With it's original meaning.

Izuku's eyes widened in shock and panic at the villain's words.

"He can hear the vestiges!?" Izuku thought with a look of panic on his face.

All For One simply chuckled in amusement.

"Is it really that surprising? Part of One For All was a quirk I gave my little brother after all. So it only stands to reason that a little of me is still in there, along with whoever it originally belonged to" he said as if it were the most obvious thing in the world.

All For One just chuckled at the horrified expression on Izuku's face, though internationally his own mind was racing to try and guess how Izuku managed to appear in Lady Nagant's mind, why he could no longer perceive the world through the woman and how it related to what was happening in UA.

To that end, All For One made a show of tapping his chin in thought.

"Now then… I find it highly unlikely that you transferred One For All to Lady Nagant…" he pondered aloud before giggling at some inside joke.

"Although I must admit that would have made things incredibly easer for me. It would definitely be ironic if you just gave the quirk over to the girl I spent so much effort into sneaking out of Tartarus to kidnap you before you could get too strong for Tomura" he chuckled out and waited for the reaction from Izuku.

To All For One's surprise and disappointment though, Izuku had no reaction.

In fact Izuku had become incredibly relaxed. Disturbingly so even, as he didn't keep his defensive stance and just stood there, staring at All For One with no emotion whatsoever.

If he still had eyes, All For One would have blinked dumbly in confusion. No man, not even the insane, had ever had such a calm and composed expression in his presence. Even All For One's good friend and doctor, still had a general fear of him, in spite of his devotion to the All For One. Only Nomus and those programmed to obey and love him were ever this calm in the presence of the ultimate villain.

And yet Izuku showed no fear whatsoever, which really threw a wrench in the All For One's plans. He'd really been looking forwards to tormenting Izuku with Lady Nagant's memories and poking holes in the young hero's beliefs in hero society and the HPSC. The pleasure he would have derived from that would almost match the information he would no doubt glean from the emotionally compromised and terrified hero.

Now All For One was both disappointed but also infinitely more curious as he studied the boy.

"Humm… Just how did you manage this…" he pondered aloud as Izuku remained motionless and silent.

When suddenly Izuku narrowed his eyes at All For One.

"You can't do anything to me" he spoke plainly and All For One froze.

The tone Izuku used gave the villain pause. It wasn't a platitude or some inspiration hero BS. It was simply a cold, hard, calculated fact.

"You would have acted immediately if you could do anything against me in here, which means you are ether powerless as just a vestige alone or you have some external backup plan" Izuku spoke coldly and robotically.

All For One simply stared dumbly at Izuku for a moment before bursting out laughing and started clapping his hands in praise.

"Bravo Deku! Bravo! You're even more analytical then I remember" All For One said with amusement before grinning evilly.

"You're right, I do have a backup plan. Lady Nagant will explode if I will it, and while it might not be enough to kill anyone around her, it will likely kill her, and we both know that's enough leverage against you, even if she is a villain. Nay, I dare say more so! After seeing her tormented past of manipulation!" All For One admits with glee as he pondered how he could leverage this against Izuku before the boy found some way around it.

Izuku had already found his solution though, and he was very glad he was still using another quirk he'd yet to reveal, lest he blush atomic red in embarrassment before his greatest enemy.

Survival Instincts.

A quirk that became stronger the more danger he was in. So in this case, faced with the greatest danger of all, it stripped away all fear and rage, leaving only logic and reason so Izuku could focus on the quirk's primary function. Providing total situational awareness and instinctual guidance to the best solution.

With this quirk, Izuku had quickly assessed All For One's ability to harm him and deconstructed the villain's attempts at subtle manipulation. Giving small truths to misdirect and conceal the whole while coaxing information out of Izuku.

And now Izuku just needed to buy time for his real body to work as he split his attention between reality and Lady Nagant's mind.

All For One was not idle though, as he pondered the drastic change in Izuku and how it could possibly relate to the information available to him, even if he wasn't really taking this situation seriously.

All For One honestly didn't really care what happened to Lady Nagant or the outcome of this encounter. He had already made his plans and set events in motion. Lady Nagant had simply been a bit of insurance and a chance to torment Izuku.

Costly insurance for the quirks he'd given her, but ultimately un-necessary for his plans. Especially since her body would likely burn up from quirk overload soon anyway.

In the end, this little back and forth had been little more then a curious and amusing distraction. The changes in Izuku's beaver and his presence here, along with the mysterious happenings at UA, were admittedly mildly concerning, but All For One had total faith in Tomura, the new All For One and his growing army of Nomus, plus the army Tomura himself had raised, which actually did bring something almost like fatherly pride to the heartless villain.

But back to the situation at hand. All For One couldn't think of anything that would send Izuku alone into Lady Nagant's mind. Not unless he miraculously developed a new quirk that he knew the previous wielders of One For All didn't have. The only quirk All For One could think of that would allow for this and was possible for Izuku to posses was…

All For One froze as he stared at Izuku with non-existent eyes that would be blown wide open.

Then he started to chuckle lightly. The chuckle then gradually built and built until he was belting out full blown evil laughter.

"DEKU! My wonderful little Deku! It's THAT quirk isn't it! One of you has finally awakened to your true potential!" All For One suddenly cried out with glee as he held out his arms towards Izuku as if reading to embrace him in a hug.

Izuku was momentarily jolted from his emotionless state before the quirk took hold again with renewed fever. In that brief moment though, panic seized Izuku.

"He knows about my quirk!" He thought before the panic was shoved to the back of his mind, letting Izuku think clearly over the new information.

All For One saw his split second reaction though and took it for confirmation of his theory.

"Hahahaha! Now I know why the good doctor's nurse suddenly disappeared! She was protecting you from me! But still, for you of all people to inherit the quirk! No, you would never use it intuitionally, even on a villain, so whatever's happening in UA wouldn't make any sense if it were exactly the same. You've inherited a mutation of it, but similar enough to accomplish this. Oh the irony! And you haven't even realized the best part yet!" All For One couldn't contain his glee as he laughed before leering at Izuku with a grin that said he knew something Izuku didn't and wouldn't like.

Izuku's mind was quickly racing though as he tried to understand what was going on without loosing focus on the outside world.

"He knows something about my quirk and the one who hid the information on it but… he doesn't actually know what it is, he's just made an educated guess based on the information he has, otherwise he would be taunting me and threatening my children. But he still knows something and that's bad enough. I have to keep him from figuring anything else out" Izuku rationalized with the help of Survival Instincts and focused on his efforts outside of the mindscape.

All For One just continued to grin giddily in a way that would terrify any who saw him and didn't have their emotions suppressed.

"Izuku my boy… it's time you knew the horrible truth and the suffering that comes with it… you-"

CRACK!

All For One was cut off by the world around him suddenly shattering like glass, leaving him isolated from the rest of Lady Nagant's mind as multicolored threads appeared, connecting from him and leading into this mental world.

Izuku then snapped out of his trance and showed a look a furry and anxiety before he grimaced and took hold of the threads. The mental link between the quirks and All For One.

And he cut them.

With a combination of Blood Mage, Mineral Healing, Mind Probe and another quirk he'd made to help with Ragdoll's quirk, Izuku excised All For One from Lady Nagant's body and mind, as he gave a powerful psychic shove to push All For One back.

The villain was stunned silent for a moment, but soon grinned again before he started laughing. This was just more confirmation that Izuku's quirk was related to who he thought it was.

"I suppose that reveal will have to wait for another time then Deku. I look forward to our next meeting, once I'm out of Tartarus… which should be happening very soon…" All For One spoke before he started chuckling again. His voice echoing as he vanished from Lady Nagant's mind, happily conceding the victory to Izuku.

After all, the information he'd learned in return was priceless.

Izuku gasped for nonexistent air as he fell to his hands and knees, panting while his heart raced.

He had kept his girls and unborn children a secret from All For One and saved Lady Nagant from the villain and his constant spying.

But All For One had still leaned too much and even already had knowledge of Izuku's quirk and it's origins that even he didn't know.

This was not good.

Izuku felt like he might vomit then pass out from the stress, if not for the pounding headache his anxiety had brought about or the fact Lady Nagant was still under the influence of his quirk and needed to be attended to.

So, Izuku took a deep breath as he collected himself…

Then blushed deeply and steam erupted from his head as he remembered how he got the information on the quirks All For One gave Lady Nagant.

"I can't believe I drove off my worst villain THAT way… what is happening to my life and what deity did I anger to turn my life into the plot of some lewd anime…" Izuku lamented as tears rolled down his cheeks.

He quickly wiped them away though and sucked it up as he finished venting and prepared to leave Lady Nagant's mind and… attend to her needs…


Q/L -

—————- Mandalay - 8

Survival Instincts

"Grants the user with totally situational awareness and an instinctive understanding of the best corse of action to survive or achieve the desired goal. The quirk responds to fear. The more danger in perceived, the more emotions are suppressed and the faster the brain processes information"

5 - ?

—————- Toga - 2

Blood Doctor

"The equal and opposite of Blood Mage as in some respects. Blood Doctor instead focuses on the manipulation of the blood in others, rather then the user's own blood. It can theoretically do many of the same things Blood Mage can, but to slightly more limited degree. Temporarily copying quirk and appearance or manipulating the blood in others to puppet them or using spilt blood as weapons. This is the most basic of uses though and it's potential is slightly offset by the fact the quirk costumes some of the user's own blood to function, forcing them to ingest the blood of others to replenish themselves. This drawback is less of an issue for the quirk's real purpose though, allowing the user to manipulate the blood of others in beneficial ways. Accelerating healing and allowing treatment diseases. With enough practice and energy, it could even modify a person's DNA and quirk, major modifications would require power on the level of One For All though"


A/N - I hope I did All For One justice with this chapter. I can't help but feel the ending was a little anti-climactic but it's hard writing OP characters when they aren't activity being OP.

Also, you have no idea how many times I mixed up All For One and One For All while writing this.

Blood Doctor was made mostly to facilitate Izuku fixing Ragdoll's quirk and is somewhat inspired by Blood Born and Code Vein.

On another note, I was contacted not long ago by someone who wanted to do an audio version of this story on YouTube. At the time of writing this he hasn't posted anything yet and I'm not sure how he's gonna get around the fact that this is a smut fic, but I gave permission and anyone who wants to check it out can look up Koshoo on YouTube. From what little I checked out he uses simple text to speech for his videos.