Y/N is seen near one of the League of Darkness' hideout where All for One is.

Y/N: After all the time spent on trying to find his whereabouts, I've finally found it! This must be the place where the All for One is located, it must be it. Yosh!

Y/N places his Game Driver in his waist.

GAME DRIVER!

He then pulls out his gashats and activates them.

MIGHTY ACTION X!

DANGEROUS ZOMBIE!

Y/N: Grade X-0! Henshin!

GACHAN! LEVEL UP! MIGHTY JUMP! MIGHTY KICK! MIGH~TY ACTIO~N X! A GACHA! DANGER! DANGER! DEATH THE CRISIS! DANGEROUS ZOMBIE!

Y/N: Fuhahahahahaha! I'll clear this even if it means using continues!

Y/N: Alright! Let's finish All for One once and for all!

He then goes into the hideout.

(Timeskip)

Y/N is seen fighting through the villains and even the Grimms but he won't let them stop him.

He summons Gashacon Breaker in Hammer mode and then he attacks anyone who tries to get closer to him. Some of the villains get flung far way by the hammer's hit. Some of them got their head smashed into pieces by the hammer instead. One of the Grimms tries to attack him but it he can kill it with several hammer swings.

He then changes the Gashacon Breaker mode to Blade Mode. He then slices a villain's hands who tries to do a sneak attack on him.

Villain 1: AAAHHHH!!!! MY HANDS!!!

Y/N then shuts him up by slicing him into two pieces vertically.

Another villain tries to attack him from behind but Y/N swiftly decapitate him.

Y/N also slashes several Grimms that coming his way.

He then changes the Gashacon Breaker back to Hammer Mode before he uses the Hammer Mode finisher.

GASHAT! KIMEWAZA! MIGHTY CRITICAL FINISH!

Y/N then delivers a strong energy smash to the League of Darkness' members and Grimms which causes a powerful shockwave that knocks many of League of Darkness' members.

Y/N: Now that I'm done taking care of the annoying grunts, I can search for All for One and defeat him for good.

Shigaraki, Kurogiri, Dabi, Himiko, and Twice then appear to stop Y/N.

Shigaraki: We won't let you kill sensei! Get him!

Y/N: Ho ho~

STAGE SELECT

Now they are in some kind of stadium.

Himiko: Eh?

Y/N: Let's get this party started!

Dabi: Hmph! You asked for it!

Dabi then tries to use his quirk, Blueflame, but to no avail much to his shock. Y/N take this chance to attack him but Dabi dodges it before he got hit.

Twice also tries to his quirk to create duplicates of himself but the result is the same as Dabi's

Dabi: For some reasons, we can't use our quirks, that guy must be the cause.

Y/N: Ding-ding-ding-ding-ding! You guessed correctly. My Level 0 has the ability to negate any abilities.

Dabi: Damn! That means we have to fight without our quirks. Fine, so be it. Let's do it!

Y/N: That's the spirit!

Dabi then goes to punch Y/N which he simply block before he tries kicks him in the face which also gets blocked. Y/N then counters with a kick that knocks him a bit before he dodges a knife attack from Himiko which he retaliates with an uppercut. Y/N then switch the Gashacon Breaker to Blade Mode again while Twice tries to slice him with his extremely sharp measuring tape which Y/N blocked before he retaliates with a slash which Twice dodged. Kurogiri tries to hit him from behind but Y/N simply ducks and gives him a sweep kick which makes him fall before Y/N gets up and kick him away. Shigaraki also tries to do a sneak attack on him which doesn't work and instead get a rear elbow strike to the face by Y/N.

Twice tries to attack him again with his measuring tape but Y/N blocked all of his attacks before he counters with a series of slashes until he finally stabs him in the chest, killing him.

Himiko: Twice!

Seeing Twice dies in front of her angers Himiko so much that she tries to rush at Y/N with such great speed that she almost managed to stab him despite his attempt to block her attacks but he finally can kick her away and knocking her out.

Dabi then tries to give him a roundhouse kick which makes him duck and Y/N tries to retaliate with a sweep kick which Dabi avoids by jumping over it.

Y/N then gets up and avoid an attack from Shigaraki and Kurogiri.

Shigaraki: Tch.

He then keeps fighting both of them, dodging their attacks until he finds an opportunity to knock them out before he dodged an attack from Dabi and then fight some more against him before he finally managed to get some hit at him with some cuts on his chest.

Dabi: Ahh!!

Y/N then see them try to stand up while being seriously injured and proceeds to finish them off.

GASHAT! KIMEWAZA! MIGHTY CRITICAL FINISH!

He then gives them a powerful energy slash which then explode and killing them off.

Y/N: Now I can deal with All for One.

He de-summon the Gashacon Breaker and head towards the All for One location as the stadium starts to disappear.

(Timeskip)

After he searched around the place, he finally finds All for One.

Y/N: I've finally found you.

All for One: Ahh, so you're Kamen Rider Genm I've heard so much about.

Y/N: Yup! And today is the day you're going down forever.

STAGE SELECT

The location changes into some kind of abandoned building.

All for One: Oh? Interesting.

Y/N: Let's dance!

All for One: We'll see about that. (Tries to use his quirks but failed) Hm? I can't use my quirks, I assume you're the one behind this.

Y/N: You got that right.

All for One: Hmph, very well. I don't need my quirks to defeat someone like you.

Both of them then start fighting, Y/N get some solid blows on All for One. But All for One also got some hits on him and the last blow to the face launching him across the room and then hitting the wall.

Y/N: (getting up) Oof. Man, he's tough. Well, this is getting interesting.

All for One: That's all you got?

Y/N: Heh, you ain't seen nothing yet.

Y/N then charges at All for One and try to get some more hits at him which get blocked except for the last hit on the gut which followed by a jumping punch to the head which gets blocked by All for One and pushes him a bit.

Y/N: I'm not done yet!

After that, he jumps and performs a diving kick which get blocked before he quickly moved in for a strong punch to the gut and then an uppercut and a spinning high kick to his face which makes him flying across the room.

All for One then gets up and runs quickly towards Y/N before giving him a quick strong punch to the face before he can even react.

Y/N: OH SHI-

Followed by several fast punches to the face before Y/N can catch one of his fists and starts giving him headbutts twice. After that he gives him knee strikes to the face several times before he kicks him away.

All for One: (getting up) Rrgghh, I won't lose to some wannabe vigilante like you!

All for One then rushes at Y/N and hits his stomach before he kicks him away which causes Y/N to hits the wall again before he gets up...

Y/N: (getting up) Damn.

And do some combo at him that ends with a kick to the head which launches him away and then summons the Gashacon Breaker Blade Mode and run towards All for One and tries to cut him with it as he stands up. All for One tries to dodges the slashes but Y/N managed to hit him in the left arm.

All for One: ARGH!

Then he continues by cutting his left arm.

All for One: *huff* *huff* Grr...

Y/N then de-summon the Gashacon Breaker and uses this opportunity to finally finish him off.

GASHAT! KIMEWAZA!

Y/N: You are a really tough opponent. But unfortunately, we must end it here.

DANGEROUS CRITICAL STRIKE!

Y/N then performs a diving kick covered by powerful energies which goes through All for One, who screams in pain before explodes.

Y/N: *huff* *huff* Man, that guy was really tough even without his quirks. Hngh, whatever, gotta go home now.

The abandoned building starts to disappear and reverts back to the hideout as Y/N leaves the place.

(Timeskip)
Azur Lane HQ

Y/N is seen being treated by Vestal.

Vestal: (Treating Y/N's bruises) Geez, commander. You were too reckless back there.

Y/N: Heh heh, sorry, sorry. Ow!

(Timeskip)
One day later

Y/N is seen almost done working on the paperworks with Yat Sen as his current secretary.

Yat Sen: Just a little more and we're done with the paperworks for now, commander.

Y/N: Great, if we keep up the pace, we will be done with these paperworks in no time.

(Timeskip)

Y/N: Whew, finally done with these papers. Thank you for the help, Yat Sen.

Yat Sen: Fufu, It was nothing, commander.

Y/N: Now I'm kinda curious with what kind of news that will appear after I killed All for One.

Y/N turns on his phone to see the news.

News Anchor: Breaking news! All for One and many high ranking members of League of Darkness were found dead when the pro heroes raid one of their hideouts. Their killer is currently unknown. However, some people reported that they saw Kamen Rider Genm leaving from the direction of the hideout before the bodies were discovered. It is unknown if he was the one who killed them or if it was just a coincidence. The police and pro heroes try to investigate thi-

Y/N: Alright, I've heard enough. I'm pretty sure Union Academy is gonna be more serious in their attempt to get me after they found out that I killed one of their most feared and most powerful enemies. Not that it will be any good for them.

Yat Sen: Just be careful, okay?

Y/N: Of course *kisses Yat Sen's cheek*, how about we have lunch together?

Yat Sen: Fufu. Sure, that sounds delightful.

Then they have lunch together.

Then the screen goes black.

SEE YOU NEXT GAME

(A/N: anyway, here's some bnuuy and other stuff I found)

(A/N: 4)

https://www.youtube.com/watch?v=rSU_YlVjmUI

https://www.youtube.com/watch?v=DeTbqLea508

https://www.youtube.com/watch?v=8Kc-Eh125NU