The Journey of Chaos (Highschool DxD x OP OC)

Prologue

The Underworld

A white-haired teen could be seen walking through the halls of a huge mansion in the underworld, his personal Void Tome in his hand.  Beside him was a dark-gray haired girl roughly the same age as the teen with icy-blue eyes conversing with him.

"What do you think Lord Sirzechs needs from us, Lord Chaos?" The girl asks.

"I do not know, Yumi dear. However, it is likely related to Kuoh, specifically Lady Rias," Chaos says pushing up his glasses, Yumi adopting a cold look.

"Rias. Why is it that she remains heiress, yet she does not put the effort to train? Lord Millicas should be heir with you tutoring him on his magic," Yumi says before softening her expression at the mention of Millicas.

"I am well aware. However, Lord Sirzechs and Lady Grayfia know not of his progress with his magic, with the young lord himself wishing for it to remain a surprise. With that being said, I will make the effort to spend some time with you after this," Chaos says, causing Yumi to blush.

"A-Are you certain? Would Lady Seekvaira not mind?" Yumi asks.

"Seekvaira allowed to be one of my wives along with Sona Sitri after I defeated Sona in a game of chess. You need not worry," Chaos replies with a rare smile.

Yumi is Chaos' mutated queen and one of his wives. After Chaos acquired his Evil Pieces, with several of his pieces mutating, he set off into the human world, specifically Japan. There he encountered Yumi, in a different form, who was exhausted fighting several stray devils and fallen angels. With one spell, he disintegrated the strays and rushed to Yumi's side, healing her the best he could. When Yumi asked what he was, he simply told her his name and origins. Despite being a devil himself, Yumi immediately accepts him and thanks him for saving her. After spending some time with Chaos, she falls in love with him and requests him to become a part of his peerage. Chaos, seeing her prowess and cold, yet kind nature, accepts her love and lets his piece flow into her. The two sharing their first kiss afterwards.

The pair reach Sirzech's office with Grayfia, his queen, standing outside with her eyes closed. "Lord Chaos, Lady Yumi, Lord Sirzechs awaits you both," She said with the usual stoic look on her face.

"My thanks, Lady Grayfia. And please, refer to me as Chaos. We are family friends, are we not?" Chaos says with a small smile on his face, making Grayfia blush a little.

"O-Of course, C-Chaos. Right this way," Grayfia stuttered before straightening herself.

Chaos and Yumi bowed before led by Grayfia into the room. Sirzechs, who was inside going through paperwork, briefly looks up from his desk and regards their presence. "Ah! Chaos! Yumi! I hope you had a good day so far?" He asks.

"Indeed, Lord Lucifer," Chaos responds, pushing his glasses up.

Sirzechs looks as if he is going to throw a tantrum. "Come on! How many times do I have to tell you? No 'Lord Lucifer'! Just Sirzechs is fine!" he pouts before Grayfia pulls on his ear, making him yelp in pain.

"One day I might," Chaos quips back with a smirk, struggling to hold in his chuckle.

Grayfia lets go of Sirzechs' ear, letting him sit down and hold his ear in pain. "Anyway, I'm sure you know this already, but there are some stray fallen angels spotted in Kuoh." he says, to which Chaos nods. "Well, I've been thinking. You're still young, as is some of your peerage members. So I'm having you and some of your peerage enrolled in Kuoh Academy!" Sirzechs exclaimed with an excited look.

Chaos sighs in annoyance. "Must I enroll in a school notorious for becoming co-ed recently and containing perverts?"

"Yep! The other Satans feel as if you haven't experienced life your age. You got to do more than copy magic and powers all day in your tome you know," Sirzechs says with a smirk.