(All For One is seen in his room, completely disappointed.)

All For One: I can't believe this Kamen Rider Black could defeat Overhaul...

(Suddenly a certain group comes in.)

All For One: Who might you be? And what do you want? 

????: My name is Cinder Fall. These are Emerald Sustrai, Mercury Black, Neo and Roman Torchwick.

Roman: As for what we want, it's an alliance between both factions. Yours and Cinder's.

All For One: And why should I?

Mercury: Because we know who is Kamen Rider Black!

All For One: You do?

Emerald: Yep. The real identity of Kamen Rider Black is Leonard Arc. He was a student at Beacon Academy until he caught a certain team of huntresses cheating on him with the four students from Haven.

All For One: I see...

Roman: And there's another detail, his brother Jaune Arc, who faked his way into Beacon, had become Kamen Rider Kuuga.

All For One: Well... I guess I could use some additional members since Muscular and Overhaul died at Black's hands.

Cinder: Good, I'll let my mistress know about this.

All For One: I thought you were the leader.

Cinder: I only serve my mistress. She is the big boss of a bigger faction.

All For One: I see... Well, let's get going.

(Timeskip)

(Jaune, Class 1-A and Class 1-B are seen hanging out in the park. Suddenly Sakurako feels a pat on her shoulder, and turns to see Mercury.)

Mercury: Hey babe, how about you leave those kids and have some good time with me?

Sakurako: Not interested.

Mercury: Oh come on, I promise to be...

Sakurako: I said I'm not interested!

(Sakurako then slaps Mercury's and he isn't happy.)

Mercury: What did you do to my pretty face?

Azuma: Oh, boo hoo. What are you gonna do?

Mercury: And who are you?

Azuma: I am her boyfriend!

Mercury: Not anymore!

Azuma: Tch, really?

DESIRE DRIVER!

Azuma: You have chosen death, pal!

Mercury: You don't scare me, kid!

SET!

SET!

Azuma: I will! Henshin!

DUAL ON! ZOMBIE AND BOOST! READY? FIGHT!

(Azuma then becomes Kamen Rider Buffa and then he gets in his fighting stance, so does Mercury. As they start fighting. Leonard sees All For One.)

Leonard: You decided to grow some spines and do something yourself, I see.

Jaune: You know him?

Bakugo: (stern) You gotta be fucking kidding me... who wouldn't know the number one villain, All For One?

All For One: Such a gentleman to remember, Kacchan. I didn't forget about any of you, young heroes either.

Leonard: What happened with Overhaul and Muscular is their own faults!

All For One: These are your last words?

Leonard: This is a threat? (clenches his fists) Unforgivable!

(Leonard prepares to transform.)

Leonard: Hen...shin!

(Then Leonard becomes Kamen Rider Black.)

Black: Kamen Rider! Black!

(Then Black and All For One jump. The villain tries to hit him, but he manages to dodge the attack. As he charges at All For One, the latter shoots two blasts at him, and then he punches his back.)

All For One: What's up, Black? The power you hold is limited to this?

(Black tries to grab All For One's arm, but gets shoved aside.)

Black: Not yet. I can't die yet.

(Black jumps at All For One, who uses telekinesis to shove him away.)

All For One: You're reckless, Black. Very well, I'll put an end on this!

(All For One tries to punch Black, who dodges the attack.)

All For One: I want you to DIE!

(All For One tries to punch Black again, but he dodges again. Back to Buffa, he is seen losing the battle against Mercury.)

Mercury: After I'm done with you, I'll rape your girlfriend as a payback for her having slapped my face!

(These words trigger Azuma as he unleashes his true power and summons a horde of zombies.)

Mercury: WHAT?

Buffa: I will fight to the end to protect Sakurako. Zombies will never fall, they will keep fighting. That's me: Kamen Rider Buffa!

(Then the zombies start approaching Black, who then kicks some of them, but the zombies get back up, and Buffa approaches him.)

Buffa: Say goodbye to your miserable life!

ZOMBIEBOOST GRAND VICTORY!

(Buffa summons the Boostriker, transforming it into Buffa Mode. He rides on and rushes Mercury, using the Boostriker to kick him into the air. He shortly jumps after and when reaching Mercury, Buffa then delivers a powerful downward punch to him onto the ground.)

Mercury: YOU'RE GOING TO PAY FOR THIS!

(Mercury then explodes, which results in his death.)

(Back to Black, he is seen still fighting All For One until Izuku charges at him.)

Izuku: DETROIT SMASH!

(Izuku then punches All For One, sending him sprawling. Black then takes the opportunity.)

Black: Thanks, Izuku.

(Black then prepares to finish All For One.)

Black: RIDER PUNCH!

(Black then punches All For One, breaking his mask.)

Black: (jumps) RIDER KICK!

(Black then kicks All For One in the chest as he screams in pain.)

All For One: AAAAARGH! NOOOOOOOOOOOOOOOO!

(All For One then explodes.)

(Timeskip)

(Next day, Leonard is seen along with his girls looking at the sunset.)

Leonard: It's so beautiful.

(In a short distance, Azuma and Sakurako share a passionate kiss.)

(Meanwhile at a certain palace, Cinder approaches a certain female figure along with the League of Villains.)

Cinder: We successfully made an alliance with the League of Villains.

????: Bad news?

Tomura: Unfortunately our boss died at the hands of this Kamen Rider Black guy.

Emerald: And a zombie brat killed Mercury.

????: (sighs) Damn it... (to Cinder) Proceed with the plan. With the League of Villains by our side, the Fall of Beacon is at hand.

Cinder: (bows) Yes, mistress.

(Then Cinder, her faction and the League of Villains walk away as a certain male figure in a business suit comes in.)

????: Start project Shadow Moon, Watts!

Watts: Yes, mistress!

(Watts walks away, leaving the woman to smirk as the screen goes black)

(Season 1 End.)