(Shouldn't go to the harem route in Helltaker)
Y/n:*yawns*

He got up, stretches out, takes a shower, dries himself, brushes his teeth, washes his face and puts on his clothes. He leaves the dorm, went towards the dorm where his future children,  their caretaker and the Devil Summoners are sleeping.

Y/n: come on, we'll be heading towards the headmaster office.

Demi-Fiend: fine.

They all got up and went to the headmaster's office to see them.

Y/n: you must be the headmasters of this academy?

????: yes forgive me I'm Jean.

????: Sirzech Gremory, the current Lucifer.

Lucifer:*mind* did he use my name as a title!? I'LL KILL HIM!!!

????: I'm Ningguang I've head about you Y/n Sparda.

Y/n: great now more people knows about my family!!

Sirzech: I want to know who is that boy next to you?

Y/n: Asura Gremory Sparda, he's*sigh* my son from the future. This is my daughter Yui Sparda and this is their caretaker 2B. Their from the future. Oh yeah meet Nahobino, Demi-Fiend, Kazuya, Aleph, Nanashi, Flynn and Raidou the devil summoners.

Sirzech: w-wait....you're Asura's father but who's his mother?

Asura: your sister uncle.

Srizech: w-what!? You also have the devil summoners!?

Demi-Fiend: oh hey Sirzech!! Haven't seen you since I kicked your ass!!

Y/n: since when!?

Demi-Fiend: oh I was wondering around in the Underworld I found him fighting in some war and I kicked his ass along with some fallen angels, angels and demons.

Y/n: cool.

Alpeh: sorry about that he sided with Lucifer since he rejected the reasons.

Ningguang: it's okay but why are you here for?

Y/n:*sigh* you heard about the death of my family?

Jean: yes we're very sorry.

Y/n: yeah now Mundus has returned and he brought back Yaldabaoth as his son.

Jean: Mundus is back!?

Y/n: yes now sealing him won't due so we have to erase him along with Yaldabaoth. But all of us are not trained enough so we have to be stronger to handle the attacks. I want them to join the academy.

Sirzech: okay you got it.

Y/n: I'm gonna speak to Saber, Jeanne, Jeanne Alter and Mashu about this.

He tells them to eat some breakfast, went towards the dorm where is his girlfriends are resting. He knocks the door.

Y/n: Saber? Jeanne? Alter Jeanne? Mashu? Are you girls there?

The door opens and Mashu was worried about Y/n.

Mashu: where were you yesterday?

Y/n: I was going to tell you four that. Archer is there is he? I can smell the food and he's wearing an apron.

Y/n: I stand correct.

Archer: what is it that you want to tell us?

Y/n:*closes the door* well I'll tell you what's going on.

He tells them everything and their reaction were shocked, confused and trying to hold their anger not to punch Y/n but couldn't because different timelines.

Saber: so you're gonna take care of the children.

Y/n: well Asura can handle himself since he's around my age and has experience in fighting.

Jeanne Alter: HOW LONG ARE YOU GONNA STAY A VRIGIN!? I WANT TO LOSE MY V CARD TO YOU!!

Y/n:*sigh* I can't understand Alter personality.
(Facts: Barely fucking understand the fate franchise as a whole because it wasn't in my radar the art style looks good even the fights I've seen from gifs looks cool but never understand the lore)

They all got up, leave and grabbed breakfast. They went to their class and went on for their day.

(Mini-Timeskip)

Y/n who was eating his lunch, he felt an aura that was dark and filled with flames. He got up and takes out Rebellion.

Y/n: something isn't right but I'll have to bring them.

He teleports his girlfriends, Nero, Archer and Ren. They were confused.

Archer: what's going on?

Y/n: come on I sense a demon. We got to deal with it.

They run towards the location where the aura is at.

(Meanwhile)

[There should be a GIF or video here. Update the app now to see it.]

????: RRRRAAAAA!!! WHERE IS HE!?

He screams in rage as he kills 10 people from his lava, melted cars, telephone poles, street lamps were everywhere. Then Y/n and the group arrived. The giant spider turns around but was disappointed.

????: Another small one. I sensed something a little bigger. What a disappointing catch.

Y/n: what a big surprise. I hope for you sake, you got something inside in that big body of yours, Phantom.

Phantom: you puny pathetic thing!!*roars* I'll step on you and those puny things like ants, HAHAHAHAHAHA!!!

He swings his claw but they all dodged. Y/n who takes out Rebellion and uses Stinger to damage the lava spider. Alter Jeanne rushes slashes one of the arms off of Phantom's body.

Phantom: AAAAHHGGGG!!

Archer takes out his bow and rapidly shot barrages of arrows. Then Kirito and his friends arrived along with Aether, his twin sister Lumine and Amber even the devil summoners arrived along with Asura.

Demi-Fiend: eat this you bug freak!!

Nahobino: Blast out!!

He and Nahobino uses Freikugel and damaged the lava spider. Kazuya summoned Cerberus while Aleph summoned Cu Chulainn as they used Fatal Sword.

Y/n: what are you guys doing here!?

Suguha: we're gonna help you!!

She, Silica, Asuna, Lumine all used a water attack that damaged Phantom since his body is lava.

Asura: eat this!! BIG BANG ATTACK!!

A ball of ki shot out of Asura's hand and exploded on Phantom as he roars in rage. He shot out a large fireball but Y/n slices it with Yamato.

Y/n: weak demon....

Phantom: I'm NOT WEAK!!!

He shot another fireball but to the ground and lava erupted out of the ground. Everyone dodged the lava.

Mashu: ahhhhhh!! Too close!!

Phantom: got you!!

He swings his claw and hits Nero and Y/n whi groan in pain. They got back up and Nero shot a bullet hitting Phantom's eye Ren shot barrages of bullets hitting Phantom's weak spots. Saber, Jeanne, Alter Jeanne strike the rest of Phantom's eyes

Phantom: MY EYE!!

He charges towards Sinon who walks backwards while taking out a Glock 19 shooting every bullet.

Phantom: DIE!!

He jumps high up in the sky, fire surrounds him and slams to the ground as Sinon closes her eyes.

Silica: Sinon!!

The dust was blown away as Y/n caught Phantom.

Phantom: what!? How!?

Y/n: eat...I must eat Mundus's flesh.

He throws Phantom and Asura jumps up punches the spider to the ground and Y/n went to Devil Trigger.
(Music stops)

Y/n: "I see a devil inside myself has awakened as well. Just like mother, aunt Vergil, Nero, V and Sparda...*giggles*

Eugeo: Y/n?

Archer summons out Kanshou and Bakuya, his signature weapons, a pair of dual swords that represent Yin and Yang. He attacks Phantom, slicing his legs off.

Y/n:*giggles* Mundus...I can't wait to strip your flesh from your body....I want to taste your body...you'll feel more pain that what I've been through.

He walks towards a beaten down Phantom, who tries to get up but couldn't.

Archer: Y/n?

Y/n: remember the red color Phantom?

Phantom: You're...the son of Dante!? How that slut birth a spawn!?

Y/n: Never....

He began to to rip out Phantom's abdomen. He screams in pain.

Phantom: HAAAAAA!!! MY ABDOMEN!!

Y/n: call my mom a...

He rips out more of Phantom's body parts as lava made in contact but he wasn't even hurt and leaves on the head of Phantom.

Y/n: A FUCKING SLUT YOU FORGOTTEN DEMON!!!

He smashes the head. He smiles and laughs.

[There should be a GIF or video here. Update the app now to see it.]

Y/n: I CAN STILL REMEMBER THE BETRAYAL!! HAHAHAHAHAHAHA!! THE PAIN I CAN STILL FEEL THE DAGGER HITTING MY BACK!!

Archer, Saber, Jeanne, Alter Jeanne and Mashu rushed towards him and hugs him. He started to cry while laughing.

Y/n:*sobs* IT'S STILL THERE!! I CAN FEEL IT!! THE BLOOD DRIPPING FROM BACK!! THE TEARS DRIPPING OUT OF MY EYES!! I CAN'T STAND IT!! WHY PEOPLE BETRAY OTHER PEOPLE!? FOR WHAT REASON!?*sobs*HAHAHAHAHAHAHAHAHA!!! BE A COWARD YOU PEOPLE ARE!! I'LL MAKE YOU RELIVE YOUR WORST NIGHTMARES!!! MUNDUS!!YALDABAOTH!! YOU BETTER BE READY BECAUSE YOU'LL FEEL MY WRATH AND MY JOY OF KILLING SLOWLY!! GILGAMESH YOU BETTER BE READY I'LL STRIP YOUR FLESH FROM YOUR BODY!! THE GAME HAS NOW JUST BEGUN-

His neck was hit and was knocked out. Archer gotten very worried as Y/n's girlfriends and son were worried about his mind might go insane.

Asura: father...

Archer:*sigh* he's remember the betrayal. It's making him go insane. Gilgamesh, why that version of me had to be a fucking dick?

Alter Jeanne: Different Timelines. I'm not so sure about Y/n. We don't know how many versions of him.
(Authors:*evil laughs*)
(I'm looking you guys!!)

Mashu: Senpai...

Saber: we're done with Phantom since hems dead. We should return to rest.

Everyome agreed and returned to the academy.

End of chapter