I will become God-Harem King of the World! [Highschool DxD/Exalted] (CLOSED)

Found inspiration, it would be a crime wasting it.
It's a tie between:
[] Kiba's request
[] Old shrine
[] Optional: do both?
The votes will continue: in the meantime, have this.
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Day 1​

Lesson 1: Magic training with Akeno-sempai

You stare at the huge pile of books Akeno-san put in front of you. Not only old-looking leather books, but also modern ones about mathematics, geometry and many modern disciplines.

"Issei-kun, the source of demonic-power is imagination." She calmly explains. "Devils only need their imagination, as well as having a good sense, to create and use magic, while magic is just knowledge to control equations, using your head and making calculations. It is something where the user uses the knowledge and calculations to know 'If I do this, this will happen'."

"So..." You put two and two together. "To use magic as a human I need to be able to make complex calculations in the brink of an eye?"

What is this, Magical Girl Lyrical Nanoha?

....Learning Starlight Breaker would be extra cool though.

"Exactly! How are your grades Issei-kun?"

"...Average?"

"Then you better try hard!" She concludes with a smile. However, you can feel something dark beneath it. She opens a book at a certain page. "First, resolve this. You need to do it in few minutes."

You blanch at the impressive wall of numbers and symbol that look like some sort of alien alphabet. Even then you are undeterred. You will show Buchou and Akeno-san that you are the best Magician they have ever seen. That should impress them into joining your harem, right? Right?

Time passes, sweat rolling down your cheek as you strain your brain in a manner you never did it before. This is very advanced material, but at the base there is the stuff that you normally study at school. There is something that you've yet to grasp, the final piece to make everything connect together in a logical manner. You could almost feel it...

And suddenly you find it. You eyes widen: it was so simple, why didn't you realize it before? Much faster than your previous attempts your complete the exercises and present the results to Akeno.

"Ara ara! This is all perfect!" Akeno-san nods approvingly. "You really have talent Issei-kun. It's a waste you're not yet a Devil."

Is this? Is this a flag? Did you raise it?

Hell yeah!

Extra training: Boosted Gear Training

"So..." You stretch in the empty lot near your house. It's night and nobody is around. "Ddraig? Please teach me how to use Boosted Gear."

[Very well. The gal here will explain too since she understands the changes.] Ddraig replies.

[I am not a 'gal' dragon, whatever that means. Worm: summon the gauntlet like you already did.]

"Boosted Gear!" The familiar gauntlet appears on your left forearm.

[To activate its power you need to attune it first. Attuning means committing a certain number of motes of Essence to an item, just as if you are sustaining the magic of a Charm. Attuned items become easy to handle, as if they are part of the user's body. Concentrate, focus your will on the purpose of using the Gear's power and inject into it motes until it reacts."

You follow her instructions. The motes of your Essence, that you see as sparkles of light, moves as fluidly as if they are a third limb on your body.

[Welsh Boost Overdrive!]

[Boost!]

You hear a mechanical voice from the gauntlet. After it you feel the forming of a third pool of Essence beside your internal and external ones: if you have to place it, you would collocate it inside the gauntlet and left to reality.

Weird.

[This is an Overdrive Pool of Essence. The motes from it can only be used for offensive goals. However, this is perfect for you as a Twilight since it grants you greater firepower and let you focus your normal reserves into defense.]

[Boost!]

After five seconds the voice is heard again.

[Normally Boosted Gear double the power every ten seconds. Here however the time is halved. The doubling will stop once the collected energy reaches the limit your body can handle or if you start using it, so you need to mind your timing.] Ddraig supplies.

Another two Boosts before you feel you have reached your limit.

[Now you can use part of the motes in the Overdrive Pool to raise your physical attributes: your strength, your speed and your endurance. Doing it will put a strain on your body and left you fatigued once the effect wears off, so be careful in its use.]

'You mean, depending on the number and strength of my adversaries I need to change my strategy to the best fitting one?'

[Yes. Some times victory will be obtained only if you are willing to gamble, but this is a lesson for another time. Now, try to raise your strength and destroy a sturdy target.]

'Alright.'

[Explosion!]

You call upon the motes and channel them into your body. Then you walk to a nearby concrete pipe and punch it with your uncovered fist.

CRACK!

Your fist leaves its print on the concrete. Your hand is fine and you don't feel pain.

You smirk: yes, you can definitely use this.

-----

A confused Rias Gremory, having just teleported, stands inside Issei's room.

His empty room.

"Where is he?" She wonders aloud.

After searching the house (finding only Issei's sleeping parents) and waiting for two hours she leaves, deciding to try her "Use Ise as a cuddling pillow and make a position as her servant more appealing" plan another day.

Lesson 2: Teach us Ddraig-sensei!

Inside your mindscape.

"Hey Ddraig: is your offer to teach me Dragon techniques still valid?" Your ask the laziest resident in your head.

"Sure." He stands up. "Summon Boosted Gear: it comes easier that way." You do it. "Now, observe."

He turns to the sky and opens his jaws: a sphere of red energy forms inside it before he fires a beam. He repeats the action, only this time the sphere leaves his mouth: once it did it grows much bigger before exploding after traveling a certain distance.

"This is called [Dragon Shot]. It basically boils down to concentrate your energy into a compressed form and then fire it, either as a beam or as a bomb. This is a basic technique that young dragons need to master before they can accede to their elemental breath."

"Looks like Elemental Bolt Attack to me."

You and Ddraig turn and stare at Bright, who is watching you while laying down in mid-air (how do she does that?!). "Elemental Bolt Attack?" You ask.

"A Charm used by the Dragon-Blooded, created to made best use of their master of Elements. It permits a Dragon-Blooded to fire a bolt of elemental energy appropriate to his aspect from his hand. It works best when used in conjunction with other people, to combine the different powers into an attack of exceptional power."

Sounds interesting. "Can you tell me how it works?"

"No. But I can show you."

She waves her hand and the scenery change. Instead of the tower you are now on a field of snow. There are people here: another Bright, watching atop a flying vehicle numerous people in armor doing some sort of kata.

Suddenly a winged robot drops down from the vehicle and flies away. The people in armor react as one man and turn towards the robot, arms outstretched.

"HA!"

At their shout numerous bolts of red, blue and white energy are fired from their hands, hitting the robot and obliterating it.

"Again!" The other Bright commands. Another robot appears and the process is repeated.

"This is when I personally supervisioned the training of my Dragon-Blooded warriors, in preparation for the ever-present threat of the armies of the Wyld." The Bright next to you comments. "Wretched as they may be, no one of my subordinates betrayed me during the Usurpation."

You just nod at her words, your eyes not leaving the warriors for even a moment. "Can I keep watching?"

"All the time you want. It will reset itself at the end and begin anew."

Half of the successive training is spent under Ddraig, while during the other half you try to decipher the secrets of the warriors of old.
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The "Adventures" will appear in a different post.