AN: Just a one-shot, based on a quote I made up. Try to guess it! (Slight Manga spoilers up to 296. You have been warned)

"So...this is where it ends." All for One's voice grates through the air as the ancient villain stares down Izuku, both of them covered in blood. All for One's right arm is little more than a mass of flesh and chunks of bone, and Izuku has cuts all of his torso, showing through his once verdant-green suit, which is now a color closer to scarlet mud.

"I suppose so. 248 years, huh? 248 fucking years, All for One. This needed to end, and you know it." Izuku growls, taking a step towards the ancient Emperor of the Underground. He pulls his battered and bloody arms as All for One merely sighs.

"But I don't think it should, young hero. I've done much...yet so little. I yearn for more. I yearn for the better. I yearn for...power. Power and undivided loyalty. Unlike some of the members of my students' group." All for One replies, a sigh in his voice

"Can you really blame Dabi? You nearly killed his sister. That's a dire offense." Izuku replies, thinking back to the incident in which All for One tried to set Fuyumi Todoroki on fire, right in front of her brother. Dabi, or rather, Touya, snapped and torched the maniacal villain, who obviously survived, and was not at all happy.

"Hm. I suppose. Tell me, how did it feel when I killed your mother? Painful, I assume. All Might seemed even more broken up about it. I wonder...did he truly love her?" All for One muse, and Izuku lets out a roar of rage, leaping at the ancient being.

A sound similar to a high-caliber rifle going off reverberates around the wasteland of a battleground as Izuku Midoriya, known as Deku, slams a fist into All for One, who goes flying, slamming through a two-foot thick slab of concrete, followed closely by a streak of green lightning flashing around the green-haired man, who is not much more than an embodiment of rage and bloodlust.

"HAHAHAHAHAHAHA! OH, IT'S BEEN TOO LONG SINCE I'VE SEEN THIS RAGE, YOUNG SUCCESSOR! TELL ME, WAS IT WHEN I KILLED YOUR MOTHER, OR YOUR TEACHER DID YOU FINALLY SNAP ON ME? I CAN'T REMEMBER!" All for One roars in joy and pain, as he reels back his left arm, which swells to a grotesque level in the spans of milliseconds, ready to unleash a powerful blast of wind and kinetic force.

"FUCK YOU!" Izuku roars in reply, slamming his right arm in the left of the ancient man, whose arm is turned into little more than paste at the impact.

"GAAAAAAAH!" All for One roars and tries to heal, only to hit with a roundhouse to the jaw, sending the bloodied man into a wall, which craters when the man hits it.

Izuku leaps towards the man, landing in front of the ancient villain, eyes burning with green electricity and rage.

"Oh...my... you really are angry this time, huh? Ow...tell me...do you think killing me will make this world better? Shigaraki is still free. So are other villains. What do you think killing me will do? Other than make you mad at yourself, huh?" All for One burbles, letting his shattered jaw heal as the Number 1 hero stalks toward him, glaring at the half-broken man in front of him.

"Killing you is something I wanted to do for 5 years. Ever since you killed Aizawa in front of my class at our graduating ceremony. I have you down, day after day, month after month, for years. I became Number 1 on the way, but you, you were always my main goal. And I am not letting you go this time, motherfucker." Izuku growls, grabbing the man by the throat.

"Ah...well then...will you give me some last words?" All for One asks, and Izuku narrows his eyes

"Did you give my mother any last words? Or Mr. Aizawa? OR ANY OF THE OTHER THOUSANDS OF PEOPLE YOU'VE KILLED!" Izuku roars, clenching down harder on the man's throat.

"Hghh...Ah...fair...point..." All for One growls and Izuku stares at him then lets out a sigh and drops the man, who wheezes when he hits the ground.

"Speak, All for One. I'm not you, so I will allow you some last words." Izuku says, and All for One chuckles darkly

"You know, I could just heal right now. Kill you before you can react." All for One notes, and Izuku merely blinks at him.

"You try that, your skull will be paste before you can another word."

"Hmph. Fair...now...do you remember what I told you at the beginning of the fight we're having today?"

"...'I see you've made it through hell. Impressive. Unluckily for you, I'm the Devil. And the Devil does not let sinners free.'"

"Yes. You remember. You do have a good memory. You always did."

"Get to your point, you bastard."

"Heh...is that any way to talk to your old man?"

"..."

"Did you not know, son?"

"I knew. I have for a while. Doesn't make it any better to hear that come out of your mouth."

"Ha...there's that fire I remember from Inko."

"Do not speak her name. You have no right too."

"...I suppose I don't, hmm? I did have to kill her, after all."

"Get to your fucking point, All for One." Izuku's tone is laced with venom and ice, like a whiskey on the rocks laced with poison.

"I will arrive there, young one. But...first, a story."

"I'm going to kill you slowly."

"I'm sure. Now...have you ever heard of the Blood-Soaked Alley incident?"

"That massacre 20 years which no one could solve? Was that you?" Izuku asks with a tired sense of finality.

"As surprising as this will sound to you, no. It was an upstart villain who called themselves 'Bloody Mary'. A charming person and they were rather interesting to meet."

"...Okay. What about it?"

"Well for one, they were transgender as well as nonbinary. Made them...a bit unpredictable, I suppose you could say."

"Oh, great, you're transphobic as well. That somehow makes a lot of sense."

"Oh, hush. I'm not a transphobe, son. There are lines I will not cross. Putting someone down for something they felt they needed to do to be themselves is one of them."

"You gave your brother a quirk out of spite, and have killed dozens for speaking out against you."

"That's different. Their life choices about who they chose to identify as didn't affect me. Rather it was their...actions, I suppose. They tried to fight me on multiple occasions. They were a good fighter as well. Powerful, yet light on their feet and smart to boot. I would be lying if I said I wasn't slightly attracted. The way they fought... was impressive. They fought very, very well."

"Is there a point to this?"

"Yes, actually. Anyway, I ended up fighting them one night. And as we fought, I saw something in their eyes. Determination like I had never seen before. A fire, for lack of a better term."

"So they were determined. Why should I care?"

"Ah ah ah. Let me get to it. This time, after I managed to pin them, I asked them why. Why had they constantly chased me down, tried to beat me? I asked, and after staring me down with those fiery eyes, they answered. You want to know what they said?"

"..."

"They said: 'Through Hell, I've come, through Hell I shall leave. But I'll be damned if I don't take the Devil with me. See you in hell, bastard.' They then detonated a bomb they had planted at our feet, killing them and wounding me severely. Took me several days to recover from my injuries, even with the help of Doctor Garaki."

"Okay. so what? They killed themselves in an attempt to kill you? What's the point behind your story?"

"Human determination is a lethal thing, Izuku Midoriya. You have so much of it, it makes me wonder. Why are you so determined to kill me, other than the hurt I've caused you. Because even men who had their families killed by me haven't chased me this hard."

"...It's not just that you murdered those two. You killed them because you could. And you've caused so much harm. The army led by Shigaraki killed Midnight, Crust, and so many fucking others. Kendo, Shishida, Mineta, and Present Mic were killed by a single Nomu. Vlad King died saving Shoji from Toga. Toga had managed to take out Snipe, Tamaki, Yanagi, and Ojiro before we captured her. 10 pros went down trying to bring in Geten. Re-Destro was killed after he broke Wash's neck. Bakugo lost an arm to Shigaraki before Yaoyorozu managed to slice it off, saving his life at the least. Mei lost an eye to a gunfight with some random PLF member. Mount Lady died fighting Gigantomachia. So many, too many, have died in the fight against you and your followers."

"Many have died on both sides. Do you think you're justified in killing merely because of that?"

"No. I don't. I don't any of this I'm doing is justified in any way at all. But I know killing you is the right thing to do."

"Patricide is a pretty high crime, you know."

"So is killing your wife and the mother of your son."

"Touché."

"Do you have anything else, All for One?"

"Hmmm...Not really, young one. But I do have something to ask you."

"What?"

"When you kill me, at least make it quick. I want at least that to be quick."

"...In that case...goodbye, All for One."

Crunch.

"...See you in Hell."

"Deku." A familiar gruff voice speaks up, and Izuku turns to see his rival and compatriot, Katsuki Bakugo, better known as Dynamight, staring at the bloody splat that was once All for One's head.

"Hey, Kacchan."

"...You actually did it. I thought you were lying."

"I don't lie very well, Kacchan, you know that." Izuku sighs, limping over to the blond man, who is still staring at the body.

"No shit," Bakugo mutters, rubbing the back of his head with a black metallic arm as he stares at his green-haired rival.

"So...what are you gonna tell the public?"

"That I killed him."

"Nobody is going to like that."

"So be it. I'm done with dealing with the reporters. They've given us enough shit."

"Heh. Finally agreeing with me for once."

"Shut up."

"But seriously. What are you going to tell everyone?"

"..."

"The Devil is Dead."

Hopefully not so bad for a one-shot? By the way, the only canon thing is the death of Midnight. The rest isn't true. Chill out. And don't get on me if you didn't know, I said it at the top.