Outside a cave we see many white fang members, Grimm and fallen angels seemingly protecting the cave from many heroes, huntsmen, and Devils. In the entrance of the cave we see Adam Taurus looking out from it, glaring at the heroes before he walks back into the cave pushing past some other white fang and fallen who were rushing out to join the fight against the heroes. Walking deeper into the cave he eventually makes it to a couple more white fang members and fallen angels working on an ancient looking door with a strange symbol on it

They were seemingly trying to open it. Adam walked up to them glaring.

Adam: You all still haven't gotten that stupid door open?!

WFM1: Sorry boss but, this door has some type of seal on it. The fallen says that its magic in nature.

Adam growls and grabs the white fang member by their collar.

Adam: I don't give a damn, I want that door open now.

He then threw them to the ground with them scurrying back to the door, terrified. One of the fallen glares at him.

Fallen: Why don't you just have patience, I swear mortals like you should have been wiped out during the Great War

Adam turns and glares at the fallen

Adam: Quiet filth, the only reason I'm tolerating you in the first place is because Salem said to work with you

Fallen: And here I thought that you didn't take orders for anybody, you're nothing but a lapdog

Adam just chuckled at this.

Adam: As if I'd be that witch's pet. Once this door is opened I will use whatever is in there to bring all humans down to their knees and use it to overthrow that hag, showing the greatness of the faunus.

Fallen: Fascinating, it'd be a shame if Salem found out about this plan of yours.

Adam turned and glared at the fallen, with them just smirking.

Fallen: I mean, I guess I could keep my mouth shut if-

They were cut off by a katana being shoved into their stomach, Adam being the one to do it. He soon cut the fallen in half to which they exploded into black feathers. The other White Fang members and Fallen Angels looked on in shock and some in fear as well. Adam soon turned and glared at the others.

Adam: Does anyone else, have something to say.

They all stood there silent causing Adam to smirk.

Adam: Good, now get back to work

All Might: That will be enough villian

Turning around, Adam was met with some heroes and hunters who managed to push their way through the army outside the cave. There stood All Might the symbol of peace, along with him was Qrow Branwen a hunter, and Serafall one of the rulers of hell. Adam growled at them while putting a hand on his katana.

Adam: Stay the hell out of my way filth, or else.

Qrow: Sorry kid, but we can't let you open that door. Not sure why myself, the Gremory just said not to let you open it.

All Might: You will be coming with us Taurus, now.

Adam let out a battle cry, causing the White Fang and Fallen Angels who were with him to charge at the heroes with him. The heroes in turn charging at them too. All Might swatted away some White Fang members who got in his way knocking them out in the process. Serafall using her water magic began killing many of the Fallen Angels. Some of the other heroes that were there clashed with the other White Fang and Fallen. Adam and Qrow were battling each other, clashing their blades. They soon got into a stalemate, struggling to push the other back.

Qrow: Listen kid, like I said before I don't know what exactly is in there but the Gremory said it's bad news so for both our sakes just come quietly.

Adam: Shut up, you damn human trash, I don't care what that so called devil king says. Once I open that door, I'll use whatever is inside there and use it to bring all humans down to their knees and show that the faunus are the superior race!!

Qrow: You're fucking insane.

  He then kicked Adam, causing him to stumble back.

All Might: DETROIT SMASH!!!!

All Might came from above intending to smash his fist into Adam, with him quickly diving out of the way leaving All Might to smash into the ground resulting in a small crater. All Might was about to continue his attack on Adam but got distracted by some fallen attacking him. Adam looked on at the fight growling.

Adam: 'At this rate I won't have any fallen left to break that seal on the door'

Adam looked back at the door, but soon he got an idea. Looking back a the small crater that the number one hero had made, he smirked.

Adam: 'But maybe I don't have to break the seal, but the door'

He gained a manic grin on his face as he turned looking at All might seeing him finishing up the Fallen Angels that attacked him. He then rushed at him slashing him in the back gaining his attention. All Might tried to slam his fist into Adam, only for him to jump out of the way.

Adam: Come on Mr. Number One I thought you were supposed to be the best.

Growling All Might continued his attack, with Adam constantly dodging his strikes while taunting him along the way. He soon backflipped out of the way of one of All Might's Strikes landing in front of the door. He chuckled at this before looking back at the number one hero, making a come at me motion causing All Might to growl before launching himself at him yelling.

All Might: TEXAS SMASH!!!!!!!

Once he got close enough he threw his punch, only for Adam to dodge out of the way allowing for his fist to make contact with the door completely shattering it. All Might looked on shocked at what he's done, Adam had an insane grin on his face. The other heroes, white fang and fallen angels looked on shocked, or horrified. Seconds later a large blast of power shot out from the now broken door, along with a blast of light pushing everyone back, with Adam stopping himself by stabbing his katana into the ground holding himself there. Soon the wave of power and light stopped revealing a mass of shadows in front of the door.

Adam began to laugh like a maniac as he got up and pulled his sword from the ground. He approached the shadow that seemed to just be swaying back and forth. 

Adam: So this is the thing that Salem wanted released, I was expecting more.

He just smirked before turning to the heroes.

Adam: None the less if you really are powerful, than destroy them

He pointed to the heroes, with them all tensing up waiting for it to attack but, it never did it just continued to sway back and forth while looking down. Adam turned to the mass of shadows irritated that it didn't follow his order.

Adam: Are you deaf, I command you to kill them.

It still continued to ignore Adam angering him further.

Adam: You damn mongrel, I am the reason as to why you're free now, you shall follow what I sa-

He was cut off by the shadow quickly moving behind him and shoving a claw like hand through Adam's chest.

Blood dripped from his mouth as he turned and looked back at the shadow, only seeing it staring at him with the white soulless eyes. A voice was then heard seemingly coming from nowhere but everywhere at the same time.

V̶̥̺͕̼̻̮̩̣ͤ̒o̷͚̯̰͆ȉ̵͙̠̩͔̮͎̌̓ͅc̗̭̞͖͈͚̝̬̔͌̿̚͘e̞̪͂̌̈͞: Ȋ̸̻̤͉̬̪ͭ̂͛ ̲̫̺͒ͤ̚͠ͅs̮̹̾̿̂̾̀e̬̯̮̓͒͘r̠͖̫̘̱ͬ͂ͭ̀v̱̖͉̘͕̳ͮ͑͘ĕ̥̪̥͎͇̗̺͚̊̿͞ ̤̟̞̞̠ͫ́n̶̻͎͖̥̻̲͋̀͐ͅo̧̖͇͖̥ͥ ̰̳̺̞̫̜̞͈ͯ́ͫ̉͟o̰̟͓̲̞͍̟͂ͦ̓͢n̅ͤ҉̩̤͇̭̰̣e̲̪̳͈̱̲̲ͬͩͤͬ͢

It's claw like hand then pulled out from Adam's chest, allowing him to slump over dead. Everyone present watched on in shock, most of them being to scared to move. The shadow looked down at the now dead body of Adam, and soon began convulsing and sputtering, confusing everyone else there. The shadow began to morph and shift. It soon morphed into a shape that looked like a child and then into what looked like a teen, seconds later a large tower of purple energy surrounded it. The tower of purple energy completely destroyed the roof of the cave, stopping the fight of the heroes and villians outside the cave and making the Grimm whimper in fear of it. Cutting over to Union Academy, we see many of the students and teachers going about their day, but was caught off guard by a boom and a sudden earthquake. Everyone looked up to the sky seeing that it had turned purple and that there was a tower of energy in the distance. Inside the headmaster's office we see the headmasters looking on shocked, although Sirzechs looked on terrified and worried.

Sirzechs: 'His seal has been broken, this isn't good'

Back over at the cave the tower of energy soon dissipated revealing someone who resembled that of a biker, he had a strange mask over the top half of his face with some blonde hair showing from behind it. A red Bandana was tied to his upper forearm. A tail that looked mechanical in nature was seen swaying left and right lazily. He also had a holster on his leg containing what looked to be a shotgun, while he also had another holster on his back containing another shotgun. 

He began rolling his neck a bit earning some pops. He then opened and closed his hand while looking down at it, soon smiling and laughing.

???: Ha ha ha, It feels good to be back.

Fallen Angel: Who the hell are you!?

The being looked at the Fallen, before smirking. He then seemingly disappeared, before reappearing in front of the fallen decapitating him, with him exploding into black feathers. He gave an evil grin. He then turns and looks at the others in the room with an evil smirk.

Serafall: W-Who are you?

He chuckled a bit before he disappeared and then reappeared in front of her lifting her chin up with his hand.

???: If you must know, I am the Demon Lord Of Gluttony, Beelzemon. And I must say you're one sweet look on the eyes.

This caused Serafall's face to turn completely red, being flustered by the Demon Lord's words.

Qrow: W-Wait Demon Lord

Beelzemon looked back at the Hunter, seeing him aiming his weapon at him along with All Might and other heroes ready to attack. Beelzemon just smirked at this. 

Beelzemon: Yes, I did say I was the Demon Lord Of Gluttony didn't I?

All Might: Well then villian you'll be coming with us

Beelzemon just look at them before he chuckled to himself.

Beelzemon: No thanks, I don't feel like it.

Qrow: Fine then I guess we'll just have to use force then.

With that Qrow swung his sword at him, only for Beelzemon to block it with his arm causing it's edge to shatter. Qrow looked at his now damaged blade surprised, though it didn't last long as Beelzemon swung his fist into his face sending him flying back. The other heroes rushed to attack him, with him parrying and blocking their strikes while. He punches one into a wall, before stomping on another's head knocking them out. He then slashes another hero in their back with his claws with them doubling over from the pain. He sees All Might rushing his way, causing Beelzemon to gain a sadistic grin. All Might threw a punch at him to which he responded with his own colliding them together causing a shockwave that pushed everyone back. They soon began clashing more and more, causing more and more shockwaves that began to collapse whatever was left of the cave. All Might then swung another punch at Beelzemon, only for him to sidestep it and then throwing his own punch into All Might's side causing the Number One Hero to double over due to the side he was hit in being the side where he received his injury.

Seeing this Beelzemon jumped back and pulled the shotgun in the holster on his back out and pointed it at All Might more so at where he had punched him. He had a sadistic smirk displayed on his face, as he pulled the trigger sending a shot right into All Might's injury, earning a bloodcurdling scream from the hero with him passing out from it. The heroes who were left standing looked on in horror, even some of the remaining White Fang and Fallen did. 

Qrow: ALL MIGHT!!

Beelzemon just smirked at this. He turned and looked at Serafall with her looking at him surprised to see him being able to take down All Might so easily. He just winked at her causing her to blush. He then leaping through the hole in the roof of the cave leaving everyone else behind. Then jumping all the way to the entrance of the cave landing down, seeing that all the other villians, Grimm and even the heroes had fled. Looking around Beelzemon soon spots a broken down motorcycle that had the White Fang symbol on it. Walking over to it, he put his hand on it allow some dark aura to began flowing all around it, soon completely covering it. Once the aura subsided, now showed a new bike, one that fits Beelzemon better.

He smiled down at it before getting on it and driving off, unbeknownst to him the some of the heroes watched as he drove off into the distance concerning them of what would happen next. We then cut over to a dark castle that rested many miles away from the cave.

We see Beelzemon pull up to the castle, parking his new bike before looking up at it a hint of nostalgia washing over him. Entering he makes his way through the halls of the dark castle soon making it to what looked to be a throne room, with 7 separate thrones sitting in it each varying in sizes. He makes his way over to a throne that held his symbol on it. As he walked over to it he hears a voice behind him.

???: Lord Beelzemon is that you.

Smirking her turns a faces his loyal minions.

Chaos Magician

Black Rabbit

Saya

Dark Star

Mima

98 Marisa

Bellestarmon

He smiled at them turning to them fully.

Beelzemon: Yes it is me, my minions

Mima: It's so good to see you again my lord.

Beelzemon: It's good to see you too Mima

Beelzemon's eyes landed on a new girl with long redish blonde hair standing next to her, to which she quickly hide behind Mima once his eyes landed on her.

Beelzemon: Mima who's that behind you.

Mima: Oh this is my newest student, master this is Marisa Kirisame

She slightly poked her head out from behind Mima looking at him nervously.

Marisa: H-Hello s-sir

Beelzemon chuckled at this, before putting on a kind smile.

Beelzemon: There's no need to be scared of me young one, I'm the most reasonable out of the other Demon Lords so feel free to talk to me if you need something.

Marisa just nodded at this. Black Rabbit then stepped up.

Black Rabbit: 𝓲丅'Ş Ğ𝕠𝕠Ｄ 丅𝕠 Şᵉᵉ Ⓨ𝕠υ ⓐĞⓐ𝓲𝔫 𝕄Ⓨ ℓ𝕠ŘＤ. ᗯᵉ'Ѷᵉ 𝒷ᵉᵉ𝔫 Ｄ𝕠𝓲𝔫Ğ 𝕠υŘ 𝒷ᵉŞ丅 丅𝕠 𝐤ᵉᵉρ 丅卄ᵉ ČⓐŞ丅ℓᵉ 𝓲𝔫 ρŘ𝕠ρᵉŘ 𝕠ŘＤᵉŘ ω卄𝓲ℓᵉ Ⓨ𝕠υ ⓐ𝔫Ｄ 丅卄ᵉ 𝕠丅卄ᵉŘ 𝓓ᵉ𝕄𝕠𝔫 𝓛𝕠ŘＤŞ ωᵉŘᵉ ŞᵉⓐℓᵉＤ ⓐωⓐⓎ

Beelzemon: Yes it's good to see that you all have been doing well since we've been gone. Now listen everyone

They all looked towards him.

Beelzemon: I want you all to search for the sealed tombs of the other Demon Lords, I want you to inform me once you've found even just one, understand?

They all nodded.

Beelzemon: Good now leave me.

Once he said that they all began to leave the room.

Beelzemon: Except you Bellestarmon, you stay

Hearing this she stopped, while the others left the room. She turned to face him.

Bellestarmon: Yes Lord Beel-

He holds his hand up stopping her. An aura then surrounded him, that soon dissipated seconds after it appeared revealing a blonde hair teenager in Beelzemon's place.

(Y/N): Let's talk as ourselves, Jes

Bellestarmon looked shocked at this before blushing, a similar aura surrounding her, that soon disappeared as well leaving a long black haired girl that was dress in cloths of a scientist.

Jes:..............Hey (Y/N)

(Y/N): Hey.....

We both stood there in silence before Jes went to say something.

Jes: Look (Y/N) I'm so sor-

She was cut off by (Y/N) hugging her.

(Y/N): I don't blame you for anything Jes, no matter what anyone else says okay.

Jes stood there surprised by this but soon she hugged him back with small pricks of tears in her eyes.

Jes: Okay.............(Y/N).

That both stood there like that for a few seconds, before they both transform back into their previous forms.

Beelzemon/Bellestarmon: No matter what we'll stay by each other's side.