This is a COMPLETED/ONESHOT crossover fanfic with High School DxD and the anime series called Manyuu Hikenchou. The main plot of this anime actually fits canon Issei's personality perfectly. So that is why I made this fanfiction attempt.

Before any reviewers/readers say anything, it is like I stated in my profile. The amount of stories I have doesn't stress me at all, simply because I don't find a reason to take fanfiction so seriously.

So I'll say it again. This is completed, which means I will not continue it. The ending at this point is ambiguous.

If you don't feel like researching what Manyuu Hikenchou is about, then the summary is stated here:

It is currently the Taiheimeji Era. It is a reign ruled by the Tokugawa shogunate. Inside this shogunate, there is a group of warriors that support the government. They are the Manyuu Clan.

In this current era, breasts mean everything. If you have breasts, you are guaranteed wealth and popularity. If you lack them, you are rarely considered "human". Members of the Manyuu Clan help raise the future big breasts. Written on a secret scroll possessed by the clan, there is said to be various techniques on how to grow big and beautiful breasts.

Hope you enjoy it.

The Dimensional Gap

"Great Red! Grant my wish!"

"…This isn't Dragon Ball Z, and I'm not a wishing Dragon, dumbass."

"Hey!"

{Partner, I know you're stupid and all, but please…don't make yourself get eaten by the Apocalypse Dragon.}

'Don't worry, Ddraig. I know what I'm doing!'

{That doesn't soothe my worry, ecchi brat.}

Issei Hyoudou smiled confidently as he stood in front of the Great Red. After a long day of spending time with the numerous women in his house, Issei had suddenly gotten an idea.

A very, very bright idea.

{More like a stupid idea.}

Ignoring Ddraig's dry comments, Issei smiled wider at the Great Red, who scowled back at him. Earlier today, Issei had convinced the Ouroboros Dragon, also known as Ophis, to send him to the Dimensional Gap. When Ophis asked him the reason why he wanted to go to her home, Issei merely stated that he wanted to talk to the Great Red.

And now here he was. However, the Apocalypse Dragon himself wasn't happy about all of this.

Who did this brat think he was? The Apocalypse Dragon was busy performing so many tricks within the Dimensional Gap, but now the Oppai Dragon was here in front of him.

Bothering the hell out of him.

"Why the hell are you here, demon brat?" Great Red asked with a menacing tone.

The self-proclaimed Harem King, shielded within his Dragon Armor, gave the Great Red a smirk.

"I've come to the Dimensional Gap to ask you something important."

"…"

Taking Great Red's silence as a sign to continue, Issei pointed to the Dragon.

"I need to make sure I maintain my reputation as a Harem-King!"

{…Why are you such a pervert?}

'Hey I'm not that much of a pervert! I'm not as bad as Matsuda and Motohama.'

{Oh yeah, you're an introvert compared to those two jokers.}

'Exactly.'

"Brat, what's the point of telling me about this stupid dream of yours?"

Issei widened his eyes and (foolishly) shook a fist at the Apocalypse Dragon.

"Hey! My dream of becoming a Harem King isn't stupid! It's very admirable!"

"…I'm getting the strange urge to beat the hell out of you right now."

Finally gaining some of his intelligence back, Issei floated away from the Great Red and kept his mouth shut. Rolling his golden eyes, the Apocalypse Dragon rose his head down to Issei's level.

"So…you want me to find a way to allow you to become a Harem-King?"

His brown eyes widening excitedly, Issei nodded like an energized dog. The Great Red narrowed his eyes, suppressing the urge to hit the boy upside the head. He then widened his eyes, suddenly thinking of an idea.

A brilliant idea.

Raising his head up, the Great Red smirked dangerously down at Issei.

"All right, brat. I'll grant your wish."

"Really?! You will?!" Issei asked as he could hardly contain his excitement.

Little did Issei know, the Great Red had taken an opportunity. The young man didn't specifically ask the Great Red on how he was going to become a Harem-King.

His body glowing with the aura of dreams and illusions, the Great Red set himself into a starting position. Smiling widely, Issei waited to see what the Great Red was going to do next.

Smirking darkly, the Great Red soared towards the host of Ddraig, causing a bright light to illuminate throughout the Dimensional Gap.

In an Unknown Dimension

Brown eyes opened, and widened in shock to see an unfamiliar sight. Issei Hyoudou looked around his surroundings in confusion.

"Where the hell am I?!"

{…You're an idiot, partner.}

'What? What'd I do now?'

{While you were spouting to the Great Red about your dream in becoming a Harem-King, you failed to specifically tell him how you were going to do so.}

"…THAT BASTARD!"

{YOU IDIOT!}

Issei gritted his teeth. The Great Red tricked him! And now he was stuck in this dimension. Wait. If he was stuck in this dimension, that meant…

"GODDAMN IT! If I'm stuck here, then that means I can't touch Buchou's Oppai!"

{…}

The Boosted Gear suddenly manifested on his left arm. Before Issei could react, he suddenly felt a burning sensation on his cheek.

"OUCH!"

{Don't go shouting out idiotic stuff like that, partner! It makes you sound like a dumbass. Then again you are, so-}

'All right! All right, I get it!' Issei shouted out in his thoughts.

Issei sighed as the Boosted Gear disappeared within his left arm. Sighing again, he looked around, and his eyes widened.

'Wait. Does it feel a little hot in here?'

{…Keep looking around.}

Complying with the Welsh Dragon's words, Issei turned around to see a pool right in front of him.

'…Is that a pool? No wait, it's a….'

Issei's eyes widened further as he realized where he was.

"I'M IN A HOT SPRING?!"

{…Do you want me to smack you again?}

'…'

"Hey! What the hell are you doing here?"

At the sound of the unknown voice, Issei turned around, and he grinned. In front of him was a woman with very long black hair. She had the appearance of a quiet, cold, and stern air about her. As she was in a hot spring, the only attire she had, was a towel that was wrapped around her.

{Partner, you're staring.}

Regaining his senses, Issei shook his head and waved his hands in defense.

"Haha, sorry. I'm a little lost around here."

The woman narrowed her eyes at the young man in front of her. The clothing he was wearing suggested that he wasn't from around here. That didn't mean he could be trusted.

"What's your name, kid?"

"…"

The woman widened her eyes a little at the lack of response from Issei.

"Didn't you hear me? I asked you for your name."

Issei was silent as he tried to think about his current situation.

'Well, I'm still not a master at using magic, so I can't teleport to another dimension at all. I can't just stay here forever!'

{Humph. You might as well get comfortable, kid. Unless you can somehow summon the Great Red, we're gonna be stuck here.}

"Hey! You will answer me when I ask something of you!"

Issei widened his eyes to see the woman walking towards him in a menacing manner. Taking a step back and waving his hands in defense, Issei chuckled nervously.

"Hey, calm down!" Issei said as he tried to placate the girl.

{…It's not working.}

Before Issei could respond, the woman was suddenly in his face. Issei took another step back, and before he knew it, he and the woman tripped, causing each other to fall in the hot springs.

"AHHH!"

"AHHHHH!"

Issei coughed out some water as he swam back up. Shaking his head to dry himself off, Issei looked up. Shaking her head and coughing out some water, the woman widened her eyes to see that her towel had fallen off.

The woman widened her eyes to see that her towel was now floating in the water. She looked up to see Issei looking at her with a strange look on his face. Her face flushing in embarrassment, the woman covered her chest, and glared at Issei.

"DON'T LOOK AT ME LIKE THAT YOU IDIOT!" She shouted out as her blush brightened.

His grin disappearing, Issei sighed as he looked at the girl. Her cold and narrowed features had dissolved almost immediately. She was now blushing like an embarrassed schoolgirl.

'She's so kawaii!' Issei thought as his grin returned.

"Oi, Ouka. That your boyfriend or something?"

Issei and the girl, her name revealed as Ouka, turned to see a white-silver haired girl clad in a towel as well. Next to her were two other females. The second female had long dark blue hair and hazel eyes. The third female had short blonde hair and light purple eyes.

At the sight of the three women, Ouka widened her eyes.

"N-no." She stuttered, much to Issei's surprise. "He's not! I don't know where the hell he came from!"

Issei was far too distracted by the sight of all these women in front of him.

{Partner…}

Wanting to not invoke Ddraig's wrath, Issei shook his head to clear his thoughts. The woman with the silver hair suddenly grinned widely. Issei widened his eyes at the sadistic look on the girl's face.

"So, kid. Ouka's saying that you're not from around here. Care to explain why?"

Looking over at Ouka, who glared at him albeit with a blush on her face, Issei sighed as he rubbed his face.

"I should've just stayed at home where I could be with Buchou and everyone else."

{Humph. That dream of becoming Harem-King is coming along greatly isn't it, partner?}