High School DxD: Cheater!

Prologue

Why?

What did I do wrong?

Why did she do that?

Was I not a good boyfriend?

All mine time on her was wasted because of that bastard!

RIAAAAASSSSS!!!!

(Flashback Start)
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Rias POV:

Right now I'm sitting on Issei's lap kissing him. I know I have Kazuki but I want Issei...bad.

"I love you, Issei." I said stroking my pawn's brown hair. He kissed me again and laughed.

"I love you too, silly girl. I want to be your boyfriend, Rias. Can we be together?" He asked and I nodded with tears of joy forming in my eyes.

Poor Kazuki. I glad he doesn't know about me and Issei though. And I'm glad Issei doesn't know about us or he would've rejected me.

"Rias, what's wrong? You were staring off in space." Issei said while gently stroking my hair.

"Nothing. I just thinking about us. I want to have a family with you Issei. One boy and two girls. Let's make that happen one day okay, Issei." I said to him and placed my head on his chest.

Kazuki POV:

DOOOONNN!

That was the sound of the large blast that exploded beside me. Quickly I dashed towards the beast and slammed my fist on its face.

"Hey sorry but I have a girlfriend to see again. So let's end this." I said as a white aura formed around my body and I hit him repeatedly across the face.

The beast scratched at my chest which connected and tattered my shirt and bloodied my chest.

"Damn it. I got too cocky!" I said as I focused all my aura and power to my fist and punched them beast and he exploded on impact.

"I can't believe that this mission to five months to complete. It doesn't matter as long as I can see my sweet Rias." I said to myself as I teleported to Lord Sirzechs mansion.

"Lord Sirzechs, I have completed my mission. Thank you for letting me stay in your mansion. Your hospitality is much appreciated." I said as I bowed.

"I told you that you can call me big bro or Zechs. No more of that Lord Sirzechs stuff." He said smiling.

"Thanks bro. I'll be leaving now. Expect for Rias to call you tomorrow flashing her wedding ring to all of you." I said to Sirzechs grinning.

"Marriage already. Well I guess that's fine because you two have been dating for three years. Well I really can't wait to make you my brother-in-law." Sirzechs said as I was about to teleport.

"Make my little sister happy!" He quickly said and before I knew it, I was back in Kuoh and outside of the ORC room.

"Welp, I guess it's time to make my entrance." I said to myself as I walked over to the club.

"The club is off limits! Only members can come here!" A girl with blue hair and a green mesh said holding out her hands in front of me.

"Huh, I heard Rias gathered some new pieces but I didn't know they could be so strong. I'll introduce myself. I'm Kazuki Sato, the rook of Rias Gremory. I'm so strong that it took a mutation rook to reincarnate me." I said grinning and the girl smiled.

"I'm Xenovia Quarta. I am a knight in service to Rias Gremory. I hope we can become friends." She said and we walked to the club room together.

"I'm gonna ask Rias to marry me today. She's been my girlfriend for three years and I just love her too much so I wanna make her my wife." I said breaking the awkward silence between the two of us.

"Rias? I thought she.... Nevermind." Xenovia started but then stopped as she frowned and sighed.

"Huh, You thought she was single right? Well I mean we used to hide the fact that we were dating when I was low-class but now I'm a middle-class devil so we can be together." I said smiling and she smiled as well.

"I love Rias with all my heart but these last few months she seemed... Distant. She would only call me when she was sad about something. And she doesn't even tell me she loves me anymore." I said sighing slightly.

"Do you hear that?" Xenovia asked as we stopped by a door. Curiously I put my ear to the door and heard moans shouting Issei.

"Issei isn't he the Red Dragon Emperor and also Rias's only pawn. I heard he's strong so I really want to fight him." I said to Xenovia and she had a sad expression on her face.

"Xenovia, what's wrong? You look sad." I said but she was focused intently on the door.

"Open the door." She said calmly and I did then I saw a terrifying sight that brought tears to my eyes. Rias was naked and on top of the boy named Issei while moaning his name.

"Issei! I love you! You're my only boyfriend and I love you with all my heart! I want to have a family with you, my adorable Issei!" Rias moaned and kissed him.

"K-Kazuki are you okay?" Xenovia asked quietly so we didn't attract any attention from my cheating girlfriend.

Silently crying, I shook my head and barged in the room to Xenovia's surprise.

"K-Kazu-kun? Th-This is um.... I'm sorry!" She said apologized while getting off him and covering herself.

"I-I lo-loved you! I was gonna ask you to marry me! I loved you and this is what I get for it! You gave him your love, body, and everything else but he only wants sex from you!" I said with warm tears rolling down cheeks.

"I'm just stupid! Please forgive me! I love you! You're my first boyfriend and I love you! Please just forget want happened here. Just let me love you now. My sweet adorable, Kazuki." Rias said putting her hand on my cheek and she was also crying.

"I'm the person your replacing. Treat her well. If you don't she may cheat on you." I said walking past Rias and Xenovia sending Rias one last glare, I left the club.

How could I've been so stupid. She never loved me. She cheats in front of my face and still claims she loves me. She obliviously never cared about me feelings.

(Flashback End)

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Sighing I wiped the tears from my face and threw the rinh I was gonna give to Rias off the cliff.

"Love is stupid. I don't ever want to feel this bad. I don't want to fall in love ever again but I.... still love her." I said as I felt myself slowly losing my temper.

"Why? What did I do wrong? Why did she do that? Was I not a good boyfriend?
RIAAAAASSSSS!!!!!" I said clenching my fist so tight that my hands started to bleed.

Why does this pain feel so bad. Why do I hate it so much. I wanted to be with Rias forever but now I can't and that hurts.

Why?

A/N: I wanted to make a new story but I wasn't sure what to do it on so, I made a story where Rias cheats. Now I don't know if Kazuki will forgive Rias yet so wait for next chapter but a harem will happen. So far it's only Akeno, Rosewessie, and Xenovia but I'm sure I'll come up with something later. Welp, Till next time. See ya later~

Harem: Akeno, Rosewessie, and Xenovia.