Outside the old school building, Issei and Kiba are facing off with Xenovia and Irina. However, Y/n and Ace...

Y/n: Why do you get to fight Sabo?!

Ace: Cause I won the Rock Paper Scissors match!

Y/n: Because you cheated!

Ace: Sounds like a skill issue to me!

Y/n: You wanna go you flaming donut?!

Ace: Bring it on you rubber headed idiot!

Erza then bonks Y/n over the head.

Y/n: Owwww!

Erza: You lost fair and square, now stop being a baby about it.

Y/n: Tsch....

Erza: No cuddles for you tonight!

Y/n: You wouldn't dare....

Erza: I would!

Y/n: Fine! Ace you can fight Sabo!

Ace smirks as Y/n and Erza go back to the sidelines with Rias, Akeno, Asia, and Koneko. Asia was glaring at Xenovia, while Y/n noticed Kiba was very angry. Erza noticed this as well./

Erza: You notice it as well?

Y/n: He's filled with nothing but hatred for those Holy Swords when he shouldn't even be, the sword didn't cause him all his pain.

Erza: He should hate the one behind the project but his hate will cloud his judgement.

Xenovia: Alright then, let's begin.

Xenovia and Irina then took off their cloaks, while everyone looked at Sabo waiting for him to the same.

Sabo: I don't wear one of those... This is my battle outfit....

Akeno: Are you sure this is okay? Should we be fighting people from the church without permission?

Rias: It's just an informal bout, not an actual official battle.

Y/n: Besides, Sabo won't let anyone die and neither will Ace, although those 2 are gonna fight until one of them passes out. That's how our fights usually go.

Sabo: He's got a point.

Irina: Because if the higher ups found out then we would all be in a bit of trouble.

Sabo: Eh the higher ups can stick it for all I care.

Irina then took off the white cloth on her arm and it turned into a katana.

Xenovia: Consider it a drill, no killing.

Xenovia then unwrapped her sword and got ready fro battle, as Kiba started to laugh.

Xenovia: Why are you laughing?

Kiba: Because. The one thing I always wanted to destroy more then anything has appeared willingly before my very eyes.

Kiba then activated his Sword Birth and the ground was filled with swords.

Y/n: UNLIMITED BLADE WORKS IS COOLER!

Erza then bonks him on the head again.

Erza: Shut it!

Y/n: Yes ma'am....

Xenovia: Ignoring him. I remember who you are now. You're a sole survivor of the Holy Sword Project.

Irina: Issei, it's totally you.

Issei: Last I check I'm still me.

Irina: Man you grew up to be hot!

Issei: Huh?

Irina: Huh?

Issei: Okay then...

Irina: I feel like fate is making fun of me right now. Because the friend I grew up with has now become a Devil. Why is this happening?

Irina: My one goal in this world was to learn how to use a Holy Sword, move far away and help everyone around. Oh, God most be testing my will to overcome this dramatic heart break. If can be strong enough, I might be close enough to him.

Issei: Do note, I don't plan on holding back.

Irina: I'm glad but, I'm sorryu Issei. This hurts me, much more then it's hurts you. But you shall now face the wrath of my Excalibur!

Irina then lunged at Issei who just smirked and summoned Shusui, blocking the attack.

Irina: That sword... It can't be!

Issei: It is! This is Shushi! One of the 21 Great Grade Swords and a Black Blade. Given to me by my master Y/n L/n-Gremory!

Erza: You gave him your old sword?

Y/n: Of course I did, he's earned it.

Irina then jumped into the air and tried to slashed Issei, who got into a stance as she descended.

Issei: Water Breathing First Form:

Shusui was then coated in a Water like substance as he slashed at Irina's katana knocking her away a bit.

Issei: WATER SURFACE SLASH!

Erza: Did you?

Y/n: Yep, I had Tanjiro train with him in his mindscape.

Erza: You never cease to amaze me.

Issei: Impressive techinque, just a bit too slow for me.

Irina: Ooo, to come back to my hometown only to be forced to fight one of my oldest friends. Fate can be so cruel.

Ace: Is she always like this Sabo?

Sabo: Sadly yes...

The two then looked at each other. Ace coated his arm in Haki and so did Sabo, the two then charged at each other and began clashing fists.

Ace: You've gotten quite stronger Sabo!

Sabo: So have you Ace!

The two then began to exchange punches and kicks, each one creating a shockwave.

Asia: I never knew Big Brother could fight like this.

Y/n: Of course he can, he's just a strong as me and Ace, though it could be because, he's half angel and half devil.

Everyone minus Erza and Y/n: EHHHHHHHHHH?!

Sabo: DID YOU REALLY NEED TO TELL HER?

Ace: WHAT ARE YOU GOING TO SAY NEXT? THAT I'M HALF DEVIL AND HALF FALLEN ANGEL?

Everyone: You just did that yourself....

Ace: God damnit...

Sabo: Eh we can explain it later, let's just continue this fight.

Ace: Smarter words have never been spoken!

Ace then sped towards Sabo, jumping into the air and went to hit him with a sledgehammer kick, only for Sabo to dodge and hit Ace in the face with his pipe, causing him to land near the others.

Ace: Damn Sabo! That actually stung a bit, still not enough though!

Ace then looked over at Issei, to see him and Irina clashing swords at a very fast pace.

Irina: I have to admit, you are quite skilled. Did you start training after I left?

Issei: Would you believe me if I said I just started last night?

Irina: Are you joking? Do you think you are being cute?

Issei then smirked.

Issei: Irina, I'm adorable.

Koneko: So when did he get good with a sword?

Y/n: Oh that, I had one of my old friends from one of my adventures long ago teach him inside his mindscape.

Rias: You can do that?

Y/n: Of course I can, Mindscape Magic isn't as hard as some people make it out to be.

Y/n then points at Akeno.

Y/n: Yours however, I've seen some fucked up shit in my life, but your mindscape scares me...

Akeno then licks her lips and laughs.

Akeno: Oh, is the great Yonko Maou scared of little ol me?

Y/n: Terribly....

Back with Kiba and Xenovia, the two continued to trade blows, Kiba picked up two different swords.

Kiba: It's time for you to burn and then freeze!!!

Kiba then started to wildly slash at Xenovia, as Y/n continued to look at him. Suddenly, a figure appeared next to him, he was transparent and no-one else could see him but Y/n.

Y/n: Oh Tanjiro? What are you doing inside my head this time?

Tanjiro: I thought I would pop in to visit. I'm looking at that boy with blonde hair, he's consumed by rage isn't he?

Y/n: He is, much like you when we faced Muzan.

Tanjiro: That rage will be his downfall.

Xenovia then broke both of Kiba's swords.

Xenovia: You're being naive!

Xenovia then slammed her sword into the ground and created a massive crater, forcing Sabo and Irina to jump out of the way.

Xenovia: The Holy Sword of Destruction. Believe me, it's name isn't just for show.

Kiba: Even split into seven, they're still that strong. Then there's going to be a lot of carnage when I destroy all of them.

Issei: Kiba....

Sabo: Careful Xeno!

Irina: Hey, Xenovia! Warn us the next time you're going to do that! Anyway I guess it's about time we finished this.

Issei: I couldn't agree more!

 Issei then charges at Irina, who tries to counter with her sword, but he begins to maneveur around her, when she tries to jump away, he's right on her tail.

Issei: Water Breathing Third Form:

Issei: FLOWING DANCE!

Irina attempted to dodge the final strike, but Issei attacked quicker then she could react and knocked her away, she landed on the ground skidding onto one knee.

Irina: Such speed, you really are something.

Issei: So are you, you have some real talent.

Irina: I thank God for my ability.

Issei: Heh, never change Irina, never change.

Kiba: Haaaa!!!

Y/n then looked over at Kiba and saw he had summoned a larger sword then usual.

Y/n: He can't handle a sword that size...

Tanjiro: Very few swordsman can handle swords of that calibur, this will hinder his speed greatly, Gyomei being one of the ones we know.

Kiba: Why don't we see which of these swords are more destructive, your Holy or my Demon!

Kiba then rushes towards Xenovia.

Xenovia: Too bad..

She then easily dodged him and hit him with the hilt of her sword surprising everyone, other then Sabo, Ace, Y/n, Tanjiro, and Erza.

Sabo: That poor boy...

Ace: Idiot....

Erza: Kiba...

Y/n: He was too reckless...

Tanjiro: This was his own downfall...

Xenovia: Your only weapons are a few swords and a little speed. Not only do you lack the strength to use a larger sword, but in the process you're sealing the speed your so proud of. Please don't tell me you didn't realize that fact.

Kiba: No... Wait....

Y/n: It's over Kiba, accept it.

Kiba looks back and glared at Y/n, who glared back.

Xenovia: You should listen to him. You should know only to fight when you're in the right mind. Funny you didn't know that, given that you're my superior.

Kiba glared at Xenovia, as with Ace and Sabo, the two started at each other. They stood across from each other.

Sabo: So you wanna wrap this up?

Ace: Yeah, Special Moves?

Sabo: Special Moves.

Y/n: Oh this is gonna get good.

Ace then began to inhale a lot of air as Sabo coated his fist in fire and cocked it back.

Sabo: FIRE

Ace: FIRE DRAGON

Sabo/Ace: FIST!/ROAR!

The two attacks hit each other dead on, causing a fiery explosion that put off a lot of heat.

Issei: ACE IS A DRAGON?!

Y/n: Not quite, Ace learned his fighting style from one of Erza's pawns.

Erza: Natsu Dragneel, he's a Fire Dragon Slayer, I have two Dragon slayers in my peerage

Issei: D-Dragon Slayers?

Y/n: Eh you don't have to worry about Natsu killing you, he will most likely just want to fight you. Gajeel on the other hand, he might actually wanna kill you. Though I'm sure Levy can keep him in line.

Meanwhile, Issei coated Shusui in Haki and Irina looked wide eyed.

Irina: Y-You know Haki?

Issei: I do, why?

Irina: I concede.

Issei: Eh?

Irina: I was told never to fight a Haki user on sight unless I knew it myself, and I'm still learning it from Sabo.

Everyone: EH?!

Y/n: Oh right, Man I really gotta fill in these details. In the Angel Faction, Sabo's Family has Haki, and for the Fallen Angel's it's Ace's. It works the same as my family.

Xenovia: If we've conculuded our matches, we'll be taking our leave.

Ace and Sabo then walk up to each other, each of them covered in burn marks.

Sabo: Your flames are getting real intense.

Ace: So are yours.

The two then fistbump.

Sabo: See ya next fight.

Ace: Better not make me wait 10 years.

Sabo: Don't worry I won't.

Xenovia and Irina then put there cloaks back on, and started to walk away.

Xenovia: Remember what we talked about earlier.

Rias: Just out of curiosity, if you don't mind telling me which Fallen Angel stole the three Excaliburs/

Xenovia: A Leader of the Girgori. His name is Kokabiel.

It was then everyone felt a murderuous aura, they expected it to be from Kiba, but it wasn't. It was coming from Y/n, who's eyes were covered by his hair.

Y/n: So he's actually here?

Issei: Y-Y/n?

Y/n then lifted his head and glared at Xenovia, who was taken a back at this.

Y/n: You listen here Exorcist, I suggest you stay away from him.

Xenovia: Did you not hear me earlier-

Y/n: I FUCKING HEARD YOU! BUT I DON'T GIVE TWO FLYING FUCKS, YOU WILL NOT GET IN THE WAY OF MY REVENEGE AGAINST KOKABIEL, HE HAS TAKEN TOO MUCH FROM ME IN MY LIFE.

Xenovia: So you-

She is then glared at by Sabo.

Sabo: I suggest you shut the hell up Xenovia.

Y/n: You will never understood what I lost that day... Erza... I'm heading to Omphalos, I need to be alone for a while with the girls.

Y/n then snapped his fingers and teleported away. With that distraction Xenovia and Irina left. Sabo however stayed behind.

Rias: Is big brother okay?

Erza: No, he's not...

Issei: What was that outburst about?

Erza: You know of his daughters Metetion and Tsuki correct?

Asia: Yes, does this something have to do with them?

Ace: In a way yes. You see 10 years ago, their mother was killed by Kokabiel.

Everyone minus Erza, Ace, and Sabo gasped at this.

Issei: You mean?

Erza: Yes...

Ace: Metetion and Tsuki are the daughters of one of Y/n's former pieces, her name was Monet.

Erza then pulls out a picture of her.

Asia: She's beautiful.

Issei: She is.

Rias: I remember her, she was so nice to me.

Akeno: She really was like a big sister.

Ace: She always did have a soft spot for kids.

Sabo: God I miss her...

Erza: She would have loved all of you, but sadly one night, Kokabiel appeared when she was running an errand, she attempted to fight him off, but sadly he was too powerful for her. Y/n arrived just as he finished the job, Kokabiel laughed at Y/n's face as he held his dying love in his arms. When we had arrived at the scene, Monet had already passed on and her piece was on the floor next to her. Y/n was broken that day... He didn't talk to any of us for weeks, he would only come out of his room when his daughters needed him. Eventually, he got over it, but he swore revenge and well.... That's why he's so strong, to avenge Monet and protect the ones he loves.

Everyone was crying at the story, even Kiba shed a tear or two. Kiba then began to walk away.

Rias: Where are you going, Kiba?

He then stopped in his tracks.

Rias: You do realize that I will not permit you to leave me. You are a Knight of the House of Gremory.

Kiba: I know President and I'm sorry.

Kiba then started to walk away.

Sabo: I'll watch him from a distance, I'll make sure nothing awful happens to him. Tell Y/n i'll be around to chat when he wants to.

Erza: I will, thank you Sabo.

Rias: Thank you, Sabo.

(Timeskip)

The next day, Y/n had returned to his old self, but there was still the pain in his eyes. Erza had to attend a meeting with her peerage and the other devil kings, so she wasn't at school that day. Y/n also noticed that during the day Issei was with Saji, who he had met a while ago as one of Sona's pieces who was quite the respectful young man to his elders. 

(Saji is also a different person in this story)

The two of them were up to something and Y/n had a feeling of what it was. So he followed them, but he also noticed Koneko following them and walked up behind her without her noticing.

Y/n: Whatcha doing Neko?

Koneko jumped surprised by Y/n's "sudden" appearance.

Koneko: Y/n?! What are you doing here?

Y/n: Most likely the same reason you are. I wanna see what my student is up to and I have a gut feeling about what it is.

Koneko then nodded, as the both of them continued to follow Issei, following him to a cafe, sitting at a table, as Y/n and Koneko sat at a table behind him, covered by some bushes. As they're waiting, they ordered some ice cream and after awhile, Saji showed up and sat next to Issei. Y/n and Koneko had overheard their discussion about the Holy Swords. Issei had asked him to help destroy them, with Saji freaking out and as he's about to leave, Koneko grabbed his shirt and they both see that Y/n and Koneko where there and heard everything.

Y/n: Watcha doing Issei?

Koneko: I'm not really surprised. Had a feeling you would try and run away.

After a little more talking and "persuading" Sanji to come with them, they began to look for Xenovia and Irina. Y/n had gotten word from Sabo that he would be focusing on trying to find Kokabiel and keep The White Dragon Emperor at bay.

Saji: Why am I here...? I mean you have Rias's rook and LITERALLY ONE OF THE YONKO MAOU on board.

Issei: We need you because the stronger we are, the better.

Y/n: Also can't have you blabbing to Rias, Sona, or Erza. Especially Erza, cause then she's gonna tell Mira, Lucy and Juvia. And if she tells them, I don't think my ass or my pelvis is gonna survive...

Issei: Dude, what do your wives do when they punish you?

Y/n: I don't wanna talk about it...

Issei: Okay then... It shouldn't be too hard to find them, they mostly wearing white cloaks.

Y/n: Either that, or they could be begging for money, Sabo did say they were awful with money.

Koneko then pulled on Y/n's sleeve.

Y/n: Sup Neko?

Koneko: Look...

Y/n then looked in the direction she was pointing.

Y/n then stared at them with a blank face.

Y/n: If Nami saw this, she would kill them both or teach them how to swindle better, both options are honestly scary...

Y/n walked up to them and they were surprised.

Xenovia: What are you doing here Yonko?

Y/n: My name's Y/n, you can call me that.

Xenovia: Okay what are you doing here Y/n?

He didn't say anything.

Xenovia: What...?

Xenovia sighs.

Xenovia; We are in need of money, so we're asking for donations.

Y/n: Did you guys spend all of your money on something stupid?

Y/n saw Irina laughing nervosuly and pressing her index fingers together, as Y/n just sighed. He then grabbed Xenovia and Irina by the hoods and dragged them away.

Y/n: Follow me.

Xenovia: Where are we going?

Y/n didn't say anything and continued to drag them, the others soon followed them.

(Timeskip)

After Y/n had gotten Xenovia and Irina off the streets, he had taken them to a restaurant and told them to order anything they wanted, and Xenovia and Irina pretty much ordered 3 of everything on the menu and started to devour everything. As they were, Y/n and Koneko sat on one side and while Issei and Saji sat on the other.

Xenovia: So delicious! Don't you agree? This is heaven!

Irina: It's like food for the soul!

Saji: Watching this is a little too intense for me...

Issei: Look like they were really hungry.

Y/n: Xenovia, how long has it been since you two ate?

Xenovia: Four days.

Y/n nearly fell out of his chair, but Koneko supported him.

Y/n: FOUR DAYS?! 

After they had ate everything, Xenovia looked like she just had a realization of some sort.

Xenovia: What just happened? Even if your one of the Yonko Maou, after I made you so angry yesterday... to be saved by a Devil must mean the end of days.

Irina: We've partially sold ourselves to the devils, how will we ever be forgiven?

Y/n: Yall are weird...

Irina: Lord, please. Have mercy on these kind souls, even if they are Devils.

After Irina finished her pray, everyone else's heads started to hurt like Crazy except for Y/n's.

Issei: How is your head not hurting?!

Y/n: Oh is that what that tickling is? Huh never noticed.

Irina: Oh, I'm sorry. Force of habit.

Xenovia: Well, why did you want to speak with us, Y/n?

Y/n: We want to help you destroy the "Excalibur".

Xenovia: What?!

After they explained the siutation, to the two of them, Xenovia spoke up.

Xenovia: I understand your situation, I am truly sorry about your wife. You can deal with Kokabiel, the rest of you can take care of one sword.

Irina looks at Xenovia shocked.

Y/n: You have my greatest thanks.

Irina: Wait a minute, Xenovia!

Xenovia: You know what the other side has. Kokabiel is dangerous, only a devil king, a heavenly dragon, or a Yonko could take him on.

Irina: Yeah, I get that buy they're Devils...

Xenovia: You know we only have a 30% chance of returning home...

Irina: Yeah, but we knew the risks before we got here. This isn't anything new.

Xenovia: True, we were sent by the higher ups. Fully prepared to sacrafice our lives for the sake of our sacred cause. Sabo however....

Irina: He kinda just showed up and they were okay with it.

Y/n: None of you are going to die, I'm going to make sure of it.

The two exorcists looked at him shocked.

Y/n: You said you had a 30% chance. We will make it 110%! I've fought along side my former enemies before, I refuse to let anyone die that doesn't deserve it.

Xenovia then smiled at him.

Xenovia; Thank you, Y/n.

The waitress then came to their table with the bill and Issei picked it and looked at it and he almost fell out of his seat.

Issei: What the hell?! You both ordered 30,000 yen worth of food?!

Y/n just took the bill and gave the waitress the money and as she she walked off she smiled, everyone looked at Y/n suprised, confused, and shocked.

Y/n: Hmm?

Saji: You just have 30,000 Yen burning a hole in your pocket?

Y/n: I mean yeah?

Issei: What, how?!

Y/n: I got a lot of money.

Issei: How much money?

Y/n: My lawyer/wife Nami was advised not to ever answer the question or she will and I quote "have Robin use THAT move again"

Y/n then looked down and Saji and Issei both recoiled in shared pain.

Issei/Saji: Dude.... Your wives are scary

Y/n: I know...

(Timeskip)

Y/n had managed to get in contact with Kiba and he met everyone at the park, and they explained everything.

Kiba: I get it... But I'm quite disappointed that someone who could wield an Excalibur would approve of their destruction.

Xenovia: Speaking of disappoitning, didn't you recently abandon your place in the House of Gremory?

Kiba then glared at her.

Xenovia: If that's the case, then you are a Stray, which means you can be executed.

Kiba; You're welcome to try.

Both Kiba and Xenovia went for their weapons and Y/n walked between them.

Y/n: Enough, there will be no fighting.

Xenovia then looked at Y/n before looking at Kiba.

Xenovia: I know you resent the Holy Sword Project and what they did. I completely understand. That incident is viewed with great distaste by those currently with the church as well. We know, and that is why the one responsible was punished, excommunicated.

Irina: His name is Valper Galilel. He's also known as the Archbishop of Annihilation.

Kiba: I know him. He's the one responsible for everything...

Xenovia: I told you one of his tools was a Stray Preist, didn't I?

Issei: You must mean Freed.

Y/n: From what Sabo told me, it's not uncommon for there to be an illusion between those who have been banned from the church. There's a high possibility Valper is involved with what's going on now as well.

Kiba: Well after hearing that. There's no reason for me to not cooperate with you.

Irina: Yay! IThen I guess it's been decided then.

Xenovia: We shall return the favor for the food you had bought for us, Y/n.

Y/n: No need, I'll always feed someone if they are hungry.

Xenovia: Thank you once again.

The two exorcists then left.

Issei: So this is good news, yeah?

Saji: This is not good news! This is not good news at all!!! Not only could we have been killed, we could have been responsible for another war with the church!!!!

Kiba: Y/n, Issei.

The two turn to Kiba.

Issei: It seems like it's our turn to help, since you always saved us.

Kiba: I want you to stay out of this Issei, Y/n I know I can't stop you from killing Kokabiel and I would be foolish to try.

Issei: Huh?

Kiba: This is my revenge. I will not you all get involved with the Excaliburs.

Issei: But We're family aren't we?! you can't tell me that I'm wrong.

Kiba: No you're not wrong. But still...

Y/n: Kiba....

He turned towards Y/n.

Y/n: You are one of my Nakama, I refuse to let a single member of my Nakama do anything alone, do yo remember the story I told you about Robin, how she told us not to rescue her all those years ago?

Kiba: I remember that story yes.

Y/n: We knew the risks of going to save her, but we went anyway and we saved her. Do you remember the day Rias and I saved you?

Kiba: Of course I do....

Kiba then recounted what had happened to him in the Holy Sword Project, how he met Rias and Y/n, and after he got done. Issei and Koneko looked at him saddned.

Saji: I didn't know you had such a tragic past and I don't care what Sona does to me to punish me for this. I'm going to help.

Koneko: I'm going to help as well.

Kiba: Koneko...

Koneko: Don't be stupid. I'd be sad if you weren't with us.

Y/n: So would I, don't forget about Brook and Traffy as well.

Issei: Me as well.

Kiba then smiled.

Kiba: I guess I lost then. And I guess we know who the real enemy is. I will accept your help, so thanks guys.

Y/n: Of course. Don't worry Monet, I'll avenge you... Even if it costs me my body...