Your POV:
You and Astaroth were waiting by Issei's house for the duel. You both wore black hoodies, trousers and shoes.
"Astaroth try and restrain yourse-," You began.
"Yeah, yeah whatever," Astaroth replied cracking his knuckles as he put a cigarette in his mouth.
You just sighed as you leaned against a wall.
You waited for a while "Bro they're here," You looked up as you saw the student council along with Serefall following them.
Serefall's POV:
"Why are you in such a rush Sona?!" I cried as I followed her and her peerage.
"Shouldn't you be working?" Sona shouted back as I just cried slowly.
"Where are we going?!" I shouted as we soon stood in front of the house of the red dragon emperor, Issei's, house.
"Look why are you here?" Sona asked, turning around.
I blushed lightly.
Flashback
I was in a meeting with the other devil kings, Sirzechs Lucifer, Ajuka Beelzebub and Falbium Asmodeus. We were sitting around a round table.
"For the next meeting I would like to propose an alliance with the demon kings as they have proven to be very powerful and we also share a common enemy, the khaos brigade," Sirzechs stated sitting on his chair.
"If you say they're powerful then I'll believe you but what makes you say this?" Ajuka asked, interested.
"First, there are 9 demon kings and they're most powerful king is called the king of darkness," Sirzechs started "He single handedly beat me, Grayfia, Serefall, Michael, Azazel, my sister's peerage and a small amount of our army."
Falbium, who is normally sleeping all the time, looked up instantly whilst Ajuka simply had his jaw wide open "He's that powerful..."
"Sirzechs and I have personally met 5 of the 9 demon kings," I stated "The king of darkness also even managed to defeat Ophis though both had to hold back or else the whole would go poof, poof, poof!" I giggled.
Ajuka just shook his head at me "An alliance would benefit us very well but we must at least give something to them as this alliance might only be favourable for us."
We all paused and realised what would we give them as this offer is really 1 sided for us. We thought for a while until the usually lazy Falbium looked at me nervously "Serefall you still need a, uh, suitor right?"
"Yeah, why?" I asked cheerfully.
"Well maybe you could marry the demon king of darkness," He stated as I just froze.
I could feel my face heat up badly "W-w-what? Why m-me?!"
"You're the only female among us, you need a heir and with this we're pretty much killing 2 birds with 1 stone," Sirzechs replied smirking "Besides, it seems you have already, lets say fallen for him."
"W-wait wha? N-no I haven't!" I blushed waving my hands about.
"Come on, I bet in your dreams you're like oh (Y/N) kiss me!" Sirzechs laughed as Ajuka and Falbium joined him.
"O-okey fine! I said as they continued laughing at me "But what am I g-going to do?"
"Well then you should visit him in the human world and live with him," Sirzechs said still laughing.
"Where d-does he l-live?" I asked.
"Find out by yourself," Sirzechs replied as they all snickered at me.
"W-wha? F-fine!"
Present
"It's t-top secret," I replied blushing as Sona just looked at me before shaking her head and continuing walking.
"My peerage and I, mainly Saji, got into a fight with a student," Sona told me.
"Don't worry I'll wipe the floor with them!" Saji smirked as Sona just sighed.
"I'm not sure if this is a complete waste of time but I hope it will be a little entertaining," Sona said as her peerage smiled confidently.
"Who dares make fun of my sister!" I growled "I shall wipe them out from the earth!"
"If you did that then you'd probably kill me too and don't even think about joining in, 2 students dead are going to be troublesome to me," Sona sighed as I just died in the inside.
"So who are you fighting?" I asked.
"Them," She pointed at two men wearing hoodies "They even smoke in our school!"
The two guys looked up and I could see their faces clearly. I gasped quietly as I froze. It was (Y/N) and Astaroth!
"S-S-Sona don't fight them!" I stuttered uncontrollably as they walked towards us.
"Don't worry we'll heal them afterwards and erase their memories so they won't even remember fighting us," Sona replied.
I shook my head "That's not what I mean..."
"Fuck you!" Astaroth growled at Sona.
I could see (Y/N) shaking his head.
"What's going on?" I saw the front door open and out came Issei.
"Issei, this dickhead thinks he can beat me in a fight!" Saji laughed pointing at Astaroth.
"Who's that?" Issei asked.
"Yo Issei it's me, your pervert friend!" Astaroth laughed.
Issei looked wide eyed at Saji "Um, I'd stay cautious if I were you..."
"Why? What's this prick gon- Argh!" Saji was cut of as Astaroth punched him in the gut sending flying into the air.
I dashed forward instantly before kneeing Astaroth straight in the stomach as he growled in pain.
"Argh!" He rolled backward as he clutched his stomach "Fuck! You bitch!"
He charged at me as he drew out a knife from his trousers. He swiped forward but I ducked before sending an uppercut to his jaw. I could see Sona and her peerage staring wide eyed at us. Suddenly Astaroth rolled backward and I realised that (Y/N) had left. He roared into the air chanting something I couldn't understand. Soon he turned into what I believe is his second form as goat horns grew out of his head.
I'd be lying if I said I wasn't a little intimidated "I won't let you harm my sister even if you are a demon king, Astaroth!" I shouted.
"D-demon king?"Sona gasped in shock as Astaroth just laughed.
Soon many decayed humans appeared behind the king of rot "KILL THEM!" He growled as the monsters charged at me.
They moved really slowly and they were mumbling under the breath. I summoned a fire spell in my hand before setting all of his troops on fire. They all soon were charred to ash.
They screeched out as I gestured for Sona and her peerage to back away "Get inside the house," I urged her "He's a lot stronger than you may think."
Sona nodded reluctantly before telling her peerage to follow her into Issei's house. He shut the door as they entered.
"YOU BITCH, DO YOU KNOW WHO YOU'RE MESSING WITH?!" He bellowed as black, stitched up dogs and cats appeared behind him.
I readied another spell before little green people appeared from the ground.
"AMAIMON WHY DO YOU ALWAYS STAND IN MY WAY!" He growled as horsetail plants grew out from them and entangled the black animals before dismantling them.
Soon a green haired teenager burst from the ground on top of what looked like a spotted green hog. Who I'm guessing is Amaimon was atop it holding onto a chain attached to the harness on the beast's face.
"Sup, I'm the demon king of earth," He mumbled as he chewed on 3 lollipops.
"Okey?" I replied awkwardly.
"Brother, our fathers doesn't exist in this world you know so you don't have to be so hostile to the devil kings here," Amaimon said "Just let it go, we're all free now."
I could see Astaroth looking down still clearly pissed that he couldn't continue his fight with me.
"How about we just have a duel later?" I offered as he looked at me.
He slowly nodded "YEAH, fine," He replied as he reverted back into his human form.
I turned to Amaimon and Astaroth "Those monsters that were summoned, are they your servants?"
They looked at me "Yes," They both replied.
"I'm wondering if you could teach me and the others of the three factions, my sisters peerage and the ORC about yourselves," I asked "Also if it isn't too much to ask, can you attend a meeting and tell the other demon kings about it as well?"
They both nodded as I realised that this was my chance to find out where (Y/N) lives!
"Also, um, c-could you please tell me where you live?" I asked as they looked at me puzzled "Because, I, uh, have to live with you now..."
AN
And that's another chapter done! By the way I'm taking this story slowly as I am waiting for the anime to be released so I can adapt my story to the dxd plot. I know I can just read the manga but I don't really like reading it so I apologise for that. Also for those who don't know that much about the demons of blue exorcist I shall include a lot of information about them on the chapter after the next one so you won't have to keep searching the internet for that stuff. Anyways I hope you enjoyed the chapter! Bye!
Wakeless