Night in Gotham. A museum security officer walks through the medieval exhibit examining them for any damage or stolen items. As he goes through the armor section, he notices something about the 14th century suit of armor that jolted a bit which is something unusual. He thinks it might be a rat inside or maybe it might be haunted. As he investigates more, out of nowhere, a bolt of lightning is struck from the heavens above and knocks the security guard down. Frightened by what had happened, he also witness the armor being shocked by the lighting, moving and jerking around frantically. It suddenly stops as the lightning kept coursing through the armor. Two yellow eyes start emitting from the empty helmet, and the armor rises up from the aftershock. The guard reasonably scared takes his taser out.
Security guard: (Shaking) Who-Who are you?! What are you?!
Armor: What year is this?
Security guard: W-What?
Armor: What year is this?
Security guard: Uh...*Gulp* 2021, sir.
Armor: So... it is time.
Security guard: Wait what do you mean it's time?
Armor: I...am the Hollow knight. I am in need to seek thy hero.
Security guard: Which hero?
Armor: The one they call Leon.
Security guard: Leon? He's back at Multiverse City. This is Gotham City.
Armor: Gotham? Why aren't I in Camelot?
Security guard: Camelot? I thought that place was just a legend.
Armor: It doesn't matter now. I must head to Multiverse City.
Security guard: Wait a minute. You can't just walk out of here. You're museum property.
The Hollow knight stretches out his arm and summons a sword from the lightning in his armor and points at the guard.
Armor: Is that a threat?
Security guard: Uh, No! Of course not! You can go. 😅
NOTE: This is the Hollow knight
Meanwhile in Multiverse City
Leon and the gang are enjoying their free time at the Cinemark theater. Bruce Wayne and Weiss' sister, Winter, were at the seats behind Leon and Ruby, with Knuckles and Brock.
Bruce: So how was the family?
Winter: Well my new step father is nice to us. I mean, he is less of an asshole than...him. But all and all, we have been good.
Bruce: I heard you were thinking about joining Cartoon Universe.
Winter: If I am to join, I will teach the soldiers there and decipline them to be the very heroes they were meant to be.
Bruce: That sounds like something Frank would say.
Winter: The Soldier? He's a lunatic.
Bruce: But he did invent that four shot rocket launcher.
Leon: Shh! We're watching something here.
Bruce and Winter: Sorry.
Afterwards, the gang are back to work patrolling around the city. Leon and Knuckles were on the rooftops looking down on the streets when they spot someone suspiciously walking towards an alleyway
Leon: See anything suspicious about him?
Knuckles: Definitely. Let's track him down.
Both of them follow him on rooftop jumping from building to building until they stop and see him walking towards a figure suited with medieval armor waiting for him at a dead end.
Leon: Who's that?
Knuckles: Looks like someone who thinks it's still the 14th century.
Leon: Maybe we can see what our guy wants with him.
Man: Look man, I don't know what you want with that kid, but you're signing your own death warrant if you're planning on destroying him.
Suited man: I only wish to speak to him for thou have no quarrel with the boy.
Man: The hell do you want to do with him then?
Suited man: I know of what's going to happen five days from now.
Leon: Then you better start talking.
The suited man and the other man see Leon and Knuckles at the rooftops and jump down to the alleyway facing them both.
Man: Oh f**k! I can't stay here.
The man starts to run but the armored one uses a lasso of lightning mildly shocking the man and pulling him back.
Suited man: You're not going anywhere.
Leon: Hey, you better let him go. He probably just came here because he didn't know better.
Man: He told me that he was gonna pay me for coming here, not get arrested or forced into this! I have a family for God's sake!
Knuckles: If that's true, then you knight guy better do what Leon says or I'm gonna make you do what Leon says.
Suited man: I am the Hollow Knight, and I don't take orders from porcupines.
Knuckles: (getting angry) I'm an echidna!
Knuckles runs to punch him but the Hollow Knight summons a shield out of lightning and shifts into a metal shield to block the punch. Knuckles then pounces towards him with both fists out and the knight uses his electricity to shock down the echidna and summons his sword.
Hollow Knight: I will show you some manners, echidna. *About to thrust his sword*
Leon: I don't think so.
Leon pulls out his lightsaber igniting it and getting in front of Knuckles to block the sword's attack.
Hollow knight: My sword is of magic. It cannot be easily broken by your lightsaber.
Leon: It's not just a lightsaber. It's also a sword with a little something called liquid titanium.
Hollow Knight: Is that even a thing?
Leon: Ever since 1984.
Leon and the Hollow Knight get into a dual with both their weapons clashing with blue sparks and lightning around the battle and Leon swings his saber towards the Knight's chainmail and staggers him and Leon stabs him in the chest. The Knight just laughs and stands back up and grabs the saber with one hand.
Hollow Knight: Boy, you really don't know who I am.
He rivets up his helm showing nothing inside the helmet.
Leon: What the hell?!
The Knight charges electricity in his hands and punches him hard enough to knock him out. The Knight then goes towards Knuckles who was trying to wake up Leon.
Knuckles: Come on man, wake up!
Hollow Knight: Your friend fought well.
Knuckles: I won't let you hurt Leon.
Hollow Knight: Leon? So that's his name. I am to speak to him immediately, after he reawakens.
Knuckles: What the hell do you want with him?
Hollow Knight: Doomsday.
Knuckles: Doomsday?
Hollow Knight: It will come in a matter of five days.
Knuckles: What the hell are you talking about?
Hollow Knight: Merlin has foreseen this in our time. Doomsday is what will end this world if we can't stop it.
Knuckles: So...is Doomsday a person or a thing?
Hollow Knight: I am not sure for certain. But we must take the boy and help him recover before I discuss it any further.
Knuckles takes Leon and the Hollow Knight has them follow them out of the alleyway, but towards the end, they're stopped by a squad of Clones and Winter leading them.
Winter: Don't take one step further.
Knuckles: Winter?
Winter: Knuckles. Take Leon and get behind the troops. We'll deal with the Knight.
Hollow Knight: I do not wish to fight thee. I have seen the boy's skill. He is an excellent warrior. Just hear thy out.
Winter: Not gonna happen. Troops, arrest him.
Clone trooper: Yes, Ma'am.
???: Necessary, it is not.
The clones stop and notice the familiar voice, and so does Winter. They all step aside and salute the small but very important person in all of Multiverse City as he walks with his cane towards the female swordsmen.
Winter: M-Master Yoda?
Yoda: Speak to him, I will, young Schnee.
Winter: Yes...of course, master Yoda.
Yoda walks towards the Knight and stands calmly in front of the armor.
Yoda: So, after all these years, came back to life, did you?
Hollow Knight: As you were, Master Yoda.
Knuckles: Yoda? Wait. You know this guy?
Yoda:*Chuckles* 900 years, I am.
Knuckles: Oh...right.(Damn. That old.)
Hollow Knight: Yoda...you know what's to come.
Yoda: I fear that the day has come. Take Leon home. Discuss this later, we will.
Winter: But... Master Yoda, he...
Yoda: Cease fire, you will, young Schnee.
Winter: yes, sir.
At the Cartoon Universe HQ, at Medic's med-bay where he used his Uber healer taking care of Leon until he woke up.
Leon:*Wakes up lightheaded* Uh...God...
Medic: Slept well, Mr. Leon?
Leon: Fegelien? What am I doing here?
Medic: Long story short, you got beat by a medieval suit of armor.
Leon: I'm sorry, what?
Medic: You uh... don't know do you?
Leon: Well where is this suit of armor?
Medic: Well, not here, obviously.
Leon leaves the med-bay and heads out to seek the knight. After hours of searching around the city, he gave up and headed back home.
Upon entering the house, he is greeted with a familiar face at the dining table.
Leon: Master Yoda! *Bows* It's an honor to have you back, sensei.
Yoda: Honored, I am, my young Padawan. Someone to talk to you, he is.
Leon:[Looking confused] Who?
He turns and sees the knight that knocked him out next to Yoda.
Leon: You?!
Hollow Knight: Please, I do not wish to fight you. How is your head?
Leon: At least you didn't punch that, metalhead.
Hollow Knight: I understand your feelings towards me, but head my warnings. For I have a message to all of you about the day HE will arrive.
Leon: Who?
Hollow Knight: In my lifetime, there was a wizard in our realm of Camelot, known as Merlin. When I became a knight in the round table, he foretold of the day that a mighty monster will come from beyond the stars to destroy this world. And I'm afraid that day is already coming. As such, Merlin has made me the messenger. When I died in battle, he immortalized me in this very suit of armor with a powerful spell that explains my thunder and lightning.
Leon: So Merlin was the one that made you all hollow?
Hollow Knight: My real body is buried within the catacombs of Camelot, that is now unfortunately lost in time.
Leon: Anyway, what is this monster you're talking about?
Hollow Knight: It is only known as Doomsday. And it will come in a matter of five days.
Leon: Five days? That's sounds like a lot of time to prepare.
Hollow Knight: Unfortunately, it won't be enough to defeat this monster.
Leon: Well then how do we stop it?
Hollow Knight: There is legend that was kept within the Tamriel region.
Leon: What legend?
Hollow Knight:*Clears throat* A long millennia ago, an ancient evil had spread all though out the regions of Gaia, and non where able to stop it. No matter how strong or smart or well attuned to the force you are, this evil will always consume you no matter what. Then, one day, when the ancient evil arrived, it was stopped in it's tracks by the hands of the heroes who had saved not only Gaia, but the rest of the Multiverse.
Leon: Who were they?
Hollow Knight: They were known as the Kyptonion son, the great Ultra Instinct user, the silver eyed warrior, the monster hero, the Great grandmaster, the Chaos wielder, the ultimate mage, the ultimate mutant, and the supreme machine. But the one who defeated this ancient evil was the one above all.
Leon: Who was he?
Hollow Knight: He was known as the hero of all heroes. They called him “The One above all”.
Leon: One above all? So basically we need those kinds of heroes to defeat this Doomsday then.
Hollow Knight: Yes. Unfortunately, Doomsday is the ancient evil that was prophesized centuries ago. We need heroes to take thier place in order to defeat Doomsday.
Leon: So the Silver eyed warrior, huh. That must be Ruby. And we all know who the Kyptonion son is. Now we need the great Grandmaster for this. Yoda...
Yoda: Fight this Doomsday, I'm afraid, I cannot.
Leon: But why? You're clearly one of the strongest Jedi in all of Gaia.
Yoda: Too old, I am. But...there is another.
Leon: You mean... Anakin?
Yoda: Nieve, he is. But, his brother however...
Leon: Luke? But he bearly knows how to use the Force.
Yoda: In time, he will. Train him, me and Anakin will.
Leon: Okay, then... So who's next on our list?
Hollow Knight: We need the Ultra Instinct user, the monster hero, Chaos wielder, Ultimate mage, Ultimate Mutant, and the supreme machine.
Leon: You said Chaos wielder, right?
Hollow Knight: Yes, indeed.
At Sonic's house
Knock knock
Sonic: *Opens the door* Hello?
Leon: Hey Sonic.
Sonic: Oh hey Leon, what's-
Leon: Sonic, we need your help fighting Doomsday.
Sonic: I'm sorry, what?
Leon: Well, it's kind of a long story...
Sonic: Who's the knight?
Leon: This is the Hollow Knight.
Sonic: And what's all this about Doomsday?
Leon: The knight here said something about it being an ancient evil that almost destroyed Gaia until a group of prophesized heroes came to stop it. And apparently, you fit into the equation.
Sonic: Me?
Leon: In the said prophecy, you are known as the Chaos wielder.
Sonic: Chaos wielder? You mean the Chaos Emeralds.
Leon: Exactly. And we already have the Silver eyed warrior, and the Kryptonian son alone with the Great Grandmaster.
Sonic: Who's the Great Grandmaster?
Leon: You might be surprised who. Anyway, we need more to complete this prophecy thingy.
Sonic: Well count me in then. Who do we need next?
Leon: Monster hero, Ultimate mage, Ultimate Mutant, and the supreme machine.
Sonic: Who the heck are those guys?
Time skip
Spiderman: That would be Wolverine, The Incredible Hulk, Iron Man, and Doctor Strange.
Leon: How would you know?
Spiderman: I just thought those names fit perfectly to the heroes in the prophet.
Sonic: It does sound right.
Spiderman: So who is this Doomsday again?
Leon: We need to get everyone here to talk about it.
Spiderman: How many?
Leon: Well because of the whole prophecy thing and saying that Doomsday is near invincible...
Spiderman: Everyone?
Leon: Everyone. Including the people you mentioned.
Time skipping to the HQ where everyone we met so far in the series is here. Kroll the Troll, Master Yoda, Son Goku and Vegeta, the Seven dwarfs, Achilles, the Justice League, Team RWBY and JNPR, the Fazbear crew, Mermaid Man and Barnacle Boy, Team Sonic, Spiderman, the monster squad Dracula, Harry, Lizzie, Frankenstein, Greg, Kang and Kodos, Woody and Buzz Lightyear, Daffy Duck and Bugs Bunny, Deadpool, Bagi and Ryo, Mario and Luigi, SpongeBob and Patrick, along with the Pharaoh's champions Slabo, Argoth, and Fakath, Luke and Anakin Skywalker, and Obi-Wan Kenobi. Gaston, the Teen Titans, Team Fortress, Charlie, Vaggie, and Angel Dust, and the Scooby Doo crew. Brock Samson, Boba Fett, Jar jar, Raiden, Vixen, Sonya, Liu Kang, Jax, and Kung Lao. Literally everyone is here.
Leon: Alright. Everybody's here.
Ruby: Should we start the meeting, Leon?
Leon: Yeah. I think it's time. Listen up everyone. We are all gathered here today to face a threat like we've never seen before.
Flash: Like we haven't already.
Leon: This threat is known to be an ancient evil that once reigned terror upon the world of Gaia.
Weiss: What happened to this ancient evil?
Leon: The knight said that it was defeated by a group of legendary heroes that he said would return one day when IT returned.
Heavy: What kind of legendary heroes?
Leon: They include the Kryptonian Son, which is Superman.
Superman: Yup. Apparently I'm one of the chosen ones.
Leon: There is also the Ultra Instinct user, the Silver eyed warrior, the Chaos wielder, the Monster hero, the ultimate mage, ultimate mutant, the great grandmaster, and supreme machine.
Goku: [To Vegeta] Did Leon just say something about Ultra Instinct?
Vegeta: I...think he did.
Leon: Whatever the case, this may be the most difficult foe we may ever face in our entire lives, but no matter how strong he is, or how magical he might be, with everyone here together, we have a chance.
Everyone agrees with the situation as the enemy they face might end them or worse, the entire world.
Leon: We only have five days to prepare for its attack. So be ready for–
Patrick: Uh guys. You might wanna look at the news.
Everyone goes to Patrick who looking at the TV.
Charlie: What's wrong, Patrick?
The news station was on and this was what the anchorman had to say.
Kent Brockman: This is anchorman Kent Brockman here...and we have some disturbing news. Recently we received word that a large meteor about the size of a house is coming to Gaia. Specifically, Multiverse City.
Hollow Knight: My God...
Batman: What?
Hollow Knight: It's already here.
Leon looks at the knight in shock. He then looks at Ruby who is utterly terrified. He understands that the situation is dire and they must act quickly.
Leon: Superman. Get half of the group ready. I'll get the rest to stop that meteor.
Superman: Understood.
Leon: Come on everyone, on me.
Half of the heroes go as fast as they can to the city and already the meteor is about to hit until Goku who was with the group starts up his kameha wave.
Goku: You all might wanna stand back for this.
Leon: [To the heroes] Give him some room, folks. I've seen this before.
Goku aims at the meteor and raises his hands in the air.
Goku: Kame...hame..HA!
The blast from Goku's hands lands towards the meteor that is now burning through the sky and towards the city square until the wave came into contact with the meteor. A huge explosion occurs in the sky. The heroes still look up in the sky as the dust fades away but there's still one object still falling from the sky.
Scout: Um, why is it still falling?
Leon: Brace yourselves.
The object lands in a hard hit making a large crater in the square. Leon and the others head to the crater through the dust as it settles. The heroes find a large creature in the crater and the Hollow Knight goes in front of Leon.
Hollow Knight: Don't go near it.
Leon: Look, it's unconscious. It's probably already dead.
Hollow Knight: This creature cannot be killed so easily like that.
Leon: What do we do then, huh?
Hollow Knight: I...I don't know.
Leon: We need to know. We don't have time for this.
The creature suddenly wakes up and Patrick sees this.
Patrick: Le-le-le-Leon...
Leon: !!
The creature gets up slowly and rises from the rubble and stands up in appearance with spikes all over its body and a muscular physic that rivals the Hulk.
Hollow Knight: It can't be...
Leon: What is it?
Hollow Knight: Leon, it's...
???: I am the scourge of the universe. I am the end of days.
Leon: What the hell?
???: I am the being that will destroy all other beings in this planet. I am the apocalypse. I am Ragnarok. I am Oblivion. I am Judgement day. I....am...
Doomsday.