(Underworld)

Rias was currently in a changing room wearing a white wedding dress. Around her neck is a scale like scarf. She looks at herself in a mirror.

Rias: This is an engagement party. So why the hell am in a wedding dress?

Riser: Because Riser wanted it.

In the back of the room an orange magic circle appeared on the ground, flames erupted from it and Riser stepped out of it.

Maid: No Lord Riser, you mustn't! Men aren't allowed in here.

Riser: Just a word with his lady and Riser will be out momentarily.

Riser approached Rias who had her arms crossed.

Riser: Look at that dress, you really are a beautiful bride my love.

Rias: I'm not a bride yet, sorry to disappoint you. So what's with the dress?

Riser: What's with the dress.

Riser puts his arm around Rias's neck and placed his hand on her shoulder.

Riser: I just want you to make a good impression on our esteemed guest my dear. After all, we need to demonstrate to the world that our two houses have joined together, right?

Rias looked at Riser with disgust on her face.

Riser takes his hand off of Rias's shoulder and walks away from her laughing.

Riser: And don't worry, you'll have a dress more stunning than that one when the time comes. Lord Riser's bride will be adorned in a gown made of flaming feathers. It's only fitting for a lady of the house of Phoenix.

Rias: A dress made of flaming feathers. I think I'd be better off killing myself.

Rias said that with disgust.

Rias touched the scarf around her neck that belonged to a Lightning Dragon Slayer. She had a sad expression on her face.

(Flashback)

Y/n: Give it back to me. When your free of this engagement.

(Flashback End)

Rias: I'm sorry Y/n. It looks you won't be getting this back.

Maid: Lady Rias, it's time.

Rias looked at one of the maids and nods.

(Engagement Party)

In the main hall of the engagement party, Akeno, Kiba and Koneko were wearing something appropriate for the occasion. They listened to Ravel gloating just a few feet away from them.

Ravel: My incredibly talented brother won himself a bride by demolishing the Gremory's, of course I had no doubt he was gonna win from the beginning, but he had to keep it close so it wasn't a complete bore.

Kiba: She's delightful.

Sona: Yes, the girl's got quite a mouth on her, doesn't she?

They look over and saw Sona walking towards them wearing a dress.

Kiba: Sona, what's up?

Sona: The outcome not withstanding, I thought it was a good match. Though, I wouldn't have complained if the end result had been a bit different.

Akeno: Thanks for the support, but I promise this thing isn't even close to being over.

Kiba: We'll get another shot at then, I'm sure. Only next time, we'll be ready for their tricks.

Koneko: Yeah screw those d-bags.

Koneko takes a sip from her drink in hand.

A burst of flames erupts from the ground as Riser appears in front of the room.

Riser: Greetings renowned devils of the underworld! On behalf of the House of Phoenix. Riser would like to thank each and every one of you for coming today! This is an historic moment for the world of devils. And I want our dear guests to be the first to know. Two great dynasties are about to become one. Lord Riser of the distinguished House of Phoenix, shall wed Lady Rias of the illustrious House of Gremory! And now...

Riser held out his hand to the right side of him.

Riser: I present to you. My bride. Rias Gremory!

Rias appeared through a magic circle right next to Riser wearing a wedding dress. The Dragon Scale scarf around her neck was waving around in the air.

The entrance doors exploded as blue lightning came into the room as multiple guards fly across the hall. The lightning grew bigger and bigger. A yell can be heard from within the lightning, looking closer everyone could see a figure within the lightning.

All the guests looked at the door shocked.

Akeno, Kiba and Koneko were all shocked to see it, but quickly realized whose lightning it belonged to. They smiled.

Rias eyes widened in surprise. She touches the scarf around her neck as tears started to form in her eyes.

The lightning soon took the form of a dragon and extended its wings. A dragon's roar can be heard as well as a familiar one.

Y/n: RISER!!!

You yelled at the top of your lungs as everyone can hear a dragon's roar mixed with your yell.

( 20 Minutes Before)

You were standing in Issei's room holding the flyer in your hand.

You heard movement from behind, you turned around and saw Issei waking up. Relief quickly ran through your body.

Y/n: Issei. You're up. How are you feeling.

You crouched in front of him as Issei held his head with his hand.

Issei: Y/n? What happened. Did we win?

You found it hard to tell him, but you had to.

Y/n: No, Issei. You guys lost.

Issei immediately stood making you stand up as well.

Issei: H-How?!

Y/n: Rias surrendered and Riser was declared the victor.

Issei: I don't believe it! There's no way Rias would just give up like that. She'd keep fighting no matter what!

Y/n: Riser was about to kill you. She surrendered to save your life.

Issei put his hand on his face.

Issei: The game. The whole thing's one big blur.

Y/n: That doesn't matter right now.

Issei: What do you mean it doesn't matter? How...

Issei's door opened, you and Issei saw Asia holding a tray with water in it, Lexie was standing right next to her holding rags. Upon seeing Issei, Asia drops the tray and ran up to him. She tackled him and they both fell on his bed.

Issei: Asia. What's the matter you okay?

Asia lifted her head up from Issei chest with tears falling down her face.

Asia: Sorry! I was just so worried about you! You were out so long. I didn't know if you'd ever open your eyes again! I was scared, Issei!

Issei: I'm sorry.

Issei sat up while Asia still continued to cry on his chest. Issei started to pat Asia's head to calm her down.

Issei: I never meant to make you worry about me like that.

Asia backed away from Issei while wiping her tears.

Asia: No. Don't apologize. You're safe, and that's the only thing that matters to me now.

You smiled at the scene before.

Lexie in her human form, walked towards you.

Lexie: I'm relieved that he woke up.

Y/n: So am I.

She took notice of the flyer in your hand.

Lexie: What's that?

Lexie pointed at the flyer you were holding. You looked down at it.

She saw the determination on your face.

Y/n: This flyer, will take me to the engagement party.

Issei and Asia overhead this, they both looked at you.

Lexie: How did you get it?

Y/n: Grayfia. She came here looking for me and gave it to me.

Lexie: You're going, Aren't you? To the engagement party.

Issei and Asia looked at you surprised.

Y/n: I made a promise. I promised that I come and save her.

Lexie: Y/n, that's a bad idea. We both saw Riser regeneration power in action. Any damage you inflict on him, he'll just heal it fast.

Y/n: I have to try. For her.

You turned around.

Lexie: I'm coming with.

You looked at Lexie slightly surprised. You chuckled.

Y/n: I figured you would.

Issei: I'm coming with.

You looked at Issei shocked.

Y/n: Bad idea. You just woke up, you're not in any condition to fight.

Issei: There's no way I miss the chance to see you take that bird brain down.

You sighed and shook your head.

Asia: I'm coming as well!

Everyone looked at Asia completely shocked.

Asia: I refuse to stay here while you all go! I'm coming with you all, I can heal any injuries that you receive! I've gotten much better at using my magic! Please, don't make me stay behind!

You continued to stare at Asia. You didn't wanna risk Issei and Asia getting hurt, but it's clear that they wanted to come, despite the dangers.

Lexie: We should let them come. Asia's right, she can heal us if we get hurt.

You closed your eyes and thought for a moment. You opened your eyes after making a decision.

Y/n: You two get dressed. We head out in five minutes.

Issei and Asia both smiled.

You turned around and walked towards the chair you were sitting at, you grabbed a jacket you had brought with you and put it on.

Y/n: Ready or not Riser. Here I come.

(Timeskip)

When Issei and Asia came back wearing their school uniform. You all stood in one spot and used the flyer. In a blink of an eye, you all found yourselves in-front of a large mansion.

You sniffed the air and caught multiple scents. You continued to sniff the air, until you caught Rias's scent from within the mansion as well as Riser's scent.

Y/n: I want you all to listen to me carefully. No matter what, stay behind me. Trust me, you don't want to be beside me. Or in front.

They all shared glances at each. They all nodded to each other.

You walked forward towards the entrance. You see two guards wearing black and gold armor. One had a spear while the other a sword and shield.

You continued to walk forward, the two guards noticed you approaching the entrance. The one with the spear stepped forward and pointed his weapon at you.

Guard: Stop! You are trespassing on property of The House of Phoenix. State your business or you'll be...

Using your lightning you appeared in front of them and cut off the guards sentence by grabbing both their heads and slamming them on the ground hard. Issei and Asia were shocked by your speed.

Issei: Holy shit! Y/n ain't messing around.

You caught more scents behind the front entrance door. You raised your leg and kicked the door open. All the guards in the hallway heard this and turned to your direction. They all readied their weapons.

Y/n: I don't got time for this!

You ran forward. A guard in front of you with a shield stood in your way. He raised his shield in a defensive position.

You punched the shield hard. The guard smirked when he saw your fist stop upon punching his shield. His smirk faded when cracking sounds can be heard. He looked terrified when the shield showed signs of cracking, your fist broke the shield and connected with his face.

The other guards grew weary from seeing this. You directed your glare at them.

You ran towards two guards. They see you coming and prepare themselves for a fight.

You jumped into the air, lightning surrounded your arms.

Y/n: Lightning Dragon--

You flew down towards them, you landed in between them as they looked at you shocked.

Y/n: Wing Attack!

You swung your arm back and hit them both making them go flying in the air.

You stood up and looked at the entrance of the hall. Riser can be heard from the other side.

Riser: And now, I present you. My bride. Rias Gremory!

You glared at the five guards who took a defensive positions.

You reeled your right arm back as lightning surrounded your entire body. You ran forward.

Y/n: Out of my way!

Your fist connected with one of the guards, from the force of your attack you blew all the guards to the door as It breaks off from its hinges.

(Present Time)

You continued to yell as your lightning sparked across the hall.

Lexie, Issei and Asia stared at you shocked.

Issei: Holy shit.

Issei mumbles. Asia nods her head in agreement while Lexie stayed quiet.

Rias looked at the lightning as she starts tearing up.

Rias: He really came.

Your lightning died down as you stopped yelling. All the guests stares at you in bewilderment.

You looked forward and saw Rias standing next to Riser. He looked at you and you glared at him.

Riser steps forward and points his finger at you.

Riser: Who do you think you are, boy?

Y/n: My name is Y/n L/n. A Lightning Dragon Slayer and I'm here to uphold the promise I made to Rias. I'm bringing her back home and no is ever gonna take anything from her ever again!

Rias blushed.

You walked towards Riser as lightning crackled throughout your body.

Riser: How dare you!

A couple of Devils gasp.

Devil: Hold on, he's a human!

Devil 2: How did a human even get here?!

Riser growled in frustration.

Riser: Guards! Seize him!

Just then multiple guards surrounded you. You stopped your advancement and prepared for a fight.

Just then Kiba and Koneko quickly intervened.

Kiba slashed two guards with an ice sword.

Kiba: We're here, Y/n. And we got your back all the way!

Koneko appeared behind you kicked and the guards away.

Koneko: Suck on that, douche.

A guard jumped forward towards you. You reeled your arm ready to punch, but Lexie quickly intervened by kicking the guard in the face making him fly across the room.

Lexie: What are you waiting for? Hurry up and save the girl.

You smiled at all three of them.

Y/n: Thanks you guys.

The remaining guards were quickly hit by a lightning strike from Akeno. You turned to face her and smirked.

Akeno: That was like super hot. Go save Rias, sparky.

Issei and Asia stood next to Lexie. Issei gave you a thumbs up, you gave him one as well. You turned your attention back to Riser.

Devil 3: Is this your doing?

Devil 4: Lord Riser, what is the meaning of this?

???: It's just a little entertainment I prepared.

Everyone in the room gasp as a new person comes into the room. His scent smelled almost identical as Rias's scent. He wore a cloak with armor that covered his chest, upper arms and shoulders. The most noticeable thing was the red hair he had. The same color as Rias's.

Rias: My brother's here?

Devil 5: It's the Great Devil, Lucifer!

Behind him, you could see Grayfia standing.

Riser: What exactly do you mean by entrainment?

Sirzechs: I watched the Game, Riser. And honestly, I was underwhelmed by you. My sister lacks your gaming experience and yet, against your considerably larger forces, she nearly had you beat.

Riser glared at Sirzechs.

Riser: It's the final result that counts, my Lord.

Sirzechs: In the past yes, but the Games don't mean what they used to. Besides, Riser, you were nearly brought to your knees by a first time competitor. I can't imagine your family's proud of the way you preformed. I think you should be given another chance.

Riser looked at Sirzechs confused.

Sirzechs: Besides, we don't have a celebration like this every day. This party could use some flair I think. You there.

Sirzechs called out to you. You could feel the stares by everyone in the room.

Sirzechs: They say you possess the power to slay Dragons. And I, for one, would like to see what you're made of, which is why I had Grayfia bring you her this evening.

Riser: I see. You want a fight.

Sirzechs: Dragon versus Phoenix, yes. I believe your guests would quite enjoy a head to head match between two powers such as yours.

Rias: No. Please, don't!

Riser: An excellent idea, my Lord. I'd be more than happy to oblige you.

Sirzechs looked back at you.

Sirzechs: And you, Dragon. There are many here who have quite an interest in seeing your abilities. Would you be kind enough to show them what you're capable of?

Y/n: I didn't come all the way here to entertain your damn guests. I came here for one thing only, and that is to save Rias. Because I know she doesn't want to go through with this marriage. And I'll make sure I put her happiness first.

Rias blushed from hearing your words.

Y/n: But if there's no other way to settle this, so be it.

Riser glared at you.

Sirzechs: So tell me, Dragon, if you're the victor, what would you like to have as your reward?

Devil 6: You can't be serious! A reward for a human!

Sirzechs: Your king has spoken. He'll get his prize despite being a human. I'm the one that's requested this of him. I must give him compensation for his trouble.

Sirzechs turned back to you.

Sirzechs: What would you like to receive? A title? Or perhaps a woman of great beauty? Ask, and if you win, you shall receive.

Y/n: I want no reward, I came here for Rias and that is all.

You smiled at Rias, she looked at you and returned the smile. She touches your scarf.

Sirzechs: Very well. Grayfia, if you would be so kindly arrange these two a place to fight. I know how Dragon Slayers can be, when it comes to fighting.

Grayfia: Yes my Lord.

Grayfia bowed to him and turned to look you both.

Grayfia: Gentlemen. This way please.

Riser: When Riser done with you Dragon, he'll take what is rightfully his.

Riser grabbed his cloaked and removed it revealing armor that covered his arm and shoulders.

Y/n: I'm gonna turn you into a pile of ashes.

You grabbed your jacket and removed it.

You and Riser both walked close to each. He was a few inches taller than you, but you didn't let that intimidate you.

You both stare at each other. Lightning crackled throughout your as steam started to emit from Riser's body.

Grayfia approached both of you.

Grayfia: You both now be teleported to the alternate space for your fight.

A magic circle appeared below both of you, in a blink of an eye, you were teleported to the alternate space.

You looked around your surrounding area and noticed the large chess piece statues around the arena. You looked up at the sky and noticed it was red with stars that filled the sky.

You noticed Riser was standing on the opposite side of the arena.

You sniffed the air and only caught Riser's scent.

Y/n: So this is the alternate space Rias and them fought in, interesting.

Sirzechs's face appeared in the sky.

Sirzechs: It's time to get started.

Rias's face also appeared in the sky. A worried look on her face.

Ravel's face appeared in the sky.

Ravel: You messed with the wrong family, human! My brother's about to tear you a new one!

Riser: Yes. He's quite the confident one, but I'll take him down a few pegs! Come, boy. Fight me!

Flame like wings sprouted behind his back. Riser flew up in the air as you continued to stare at him.

Riser noticed you standing still.

Riser: Heh, this will be too easy for Riser.

Riser flew down towards you as you continued to watch him. He raises his right arm and fire surrounded it.