High School DxD Crossover: Defying The Heavens

For the remaining twelve days, Issei didn't move at all. He didn't eat and didn't drink water. He only meditated and rotated his spiritual power inside his body.

He had to do so because ever since his spiritual power's nature changed into lightning, the flow of spiritual energy became, well, erratic.

It wasn't stable, constantly surging back and forth, bursting with dangerous power. The moment he noticed that, he immediately took it upon himself to stabilize it.

And after twelve day of continuous meditation and stabilizing, he succeeded. As of that moment, it was much calmer, similar to how it was before he fused with the lightning, although with some differences.

Before, his flow of spiritual power in his profound veins and dantian was calm and serene, like a calm turtle. But now, it was bursting with power, ready to lash out at any moment, like a ferocious tiger.

Such a change was unavoidable since he fused with the wildest of the nature's elements. Either way, aside from the change in the nature of his spiritual power, there was another significant change.

Every once in a while, lightning would crackle in his profound system. That, although it seemed detrimental, was, in fact, an extremely good development. Because of the constant surge of electricity, his cultivation was improved, and now, although it would still take the same time to reach the sixth level of the Nascent Profound Realm, his spiritual power would fill at a much greater speed.

When he finally finished meditating, it was morning outside. Also, it had been exactly one month since he entered the room.

Issei then carefully opened his eyes and looked at the blackened room. His eyes, which were chocolate-brown before, were now a much lighter color, although still brown. But, there was a difference. In them boundless fierceness could be seen, along with serenity.

Such contrast was because of the lightning and Issei's personality. Issei was usually serene while lightning was fierce. Normally, those two things could not coexist, but because of the fusion, both contrasting characteristics were made possible in a single person.

"It has been one month..." Issei said softly. He then slowly got up from the ground and looked around the black room.

He then raised his left hand, looking at the mark of the Tiger Profound System, a medium ranked profound system. Such a mark was simply a drawing made by Shinso to fool others.

He then raised his right hand, on which the Grim Reaper's Symbol was hidden with a special type of paint.

As he looked at his two hands, Issei's light brown eyes flashed, quickly becoming an ethereal azure color. His hair, that was normally brown, became a light blue. In his hands, a ball of lightning appeared. All around him, lightning flowed around, making him seem like a lightning god.

That was how Issei looked when he activated the lightning power inside him. Strangely enough, there was no difference in the expenditure of spiritual power in this mode when compared to his normal mode.

"This mode..." Issei began as more and more lightning began to appear around him, flowing in the air, "Will be called Lightning Incarnation!"

His current mode, Lightning Incarnation, allowed him to freely control lightning. He could make lightning envelop his body, create lightning, mold lightning... he was like a sovereign of lightning.

He then closed his eyes and called the lightning back the lightning. Immediately, he turned normal. When he opened his eyes again, they were a light brown color.

"Good, now I just need to check some things," Issei said in satisfaction. Right now, he would use all of the abilities he obtained since coming here, just to see if everything was in order.

Bringing out Gan Jiang and Mo Ye, he covered them in spiritual power.

"First Level, Defense!" Issei exclaimed as the blade were brought in front of him in a cross position, a defensive, quasi-impenetrable aura around them. According from what he could understand from its power, it could defend one attack from a person up to two levels above him and a martial skill up to the sixth rank.

"Second Level, Counter-attack!" This time, his blades that were in front of him in a defensive position slashed forward in an arc, bringing with it the power the power of three times his normal attack power.

Immediately after the counter-attack skill finished its movement, he exclaimed, "Heavenly Strike!" At that moment, the blades slashed forward with the power of fifteen times a normal attack of his.

Seeing that all was in order with regards to the Heavenly Double Swords Might, Issei called back both swords. He then concentrated spiritual power in his hands and exclaimed, "First Way, dense!"

Immediately, a lightning wall appeared in front of him. The power contained in that lightning barrier was significantly weaker than when he used the lightning within him, but was still considerable.

"Second Way, Attack!" At that moment, two spheres of lightning, both pitiful when compared to his on the Lightning Incarnation mode appeared and sped forwards, hitting a near by wall.

"Third Way, Movement!" This time, lightning build up beneath his feet. He then dashed forward, at a speed ten times greater than normal.

"Fourth Way, Enhancement!" Instantly, lightning entered his arms as they increased his strength.

Seeing that he could still use all four ways, Issei was pleased. Although they paled in comparison to when he freely used lightning on Lightning Incarnation state, he was glad that he could still use them. He decided that in case he didn't want to show off his true power and needed to keep a lower profile, he would use them.

Finally, Issei used his last skill, Illusionary Palm. As the previous skills, it worked perfectly.

Now that he was sure that he could perfectly use all martial skills, Issei breathed a sigh of relief. At the start, he had been scared that the lightning had somehow messed with his body and made him forget some of the skills.

Since he could still use all of them, Issei decided to head out and meet with Sa Ji. Just as he was about to open the door, he finally remembered something.

Looking black at the completely destroyed and black room, he sweat-dropped. How the hell was he supposed to explain the room's condition to Sa Ji?

He couldn't possibly tell him that he learned Four Ways Of The Lightning, neither the other two skills. He knew that if Sa Ji were to know, more and more people would find out. That was what feared the most.

True, he wanted to become the number one disciple of the school, but not at the moment. He was too weak.

Shinso had told him countless times that the world they lived in followed the law of the jungle. Survival of the fittest.

It was a world where the world prey on the weak, where the strong are truly powerful. It was also a world full of merciless people.

He knew, that by nature, humans were greedy and jealous. If the number one disciple of the school were to know that Issei had the potential to surpass him, Issei was sure that he would do everything possible to make him disappear.

Because of that, Issei was determined to only rise in power when he was strong enough to take on every disciple in school. Only then would his position as the number one disciple be safe.

As such, because of all that, Issei decided that he would pretend that he didn't learn any of the skills during his stay here in his month, and would pretend that he spent his time reading the books that Sa Ji had brought him and cultivating.

But, because of the destruction caused by his power of lightning, Issei was unsure of how he should explain such a room to Sa Ji.

In the end, after thinking for a couple of minutes, Issei decided that he simply wouldn't let Sa Ji enter the room. He had no reason to, anyways. Furthermore, as far as Issei was concerned, he had the only key available, so he shouldn't need to worry about people entering the room.

With that line of thought, he could finally dispel his worries and calmly walk outside the destroyed room and onto the corridor.

Just like the first time that he came there, it was empty. Looking around for a bit, Issei decided to wait by his door for Sa Ji, since he knew that he would be coming soon.

As expected, not even ten minutes later, Sa Ji entered the building, intending to get Issei and then bring him to do some important stuff that she ordered him to do.

Much to his surprise, Issei was already outside waiting for him when he arrived. Seeing that, he raised his arm and waved it, "Hey, Junior Brother Issei!"

Startled by the voice, Issei looked at the entrance and saw Sa Ji entering the corridor. Immediately, Issei's contrasting personality of fierce and serene disappeared, replaced by a bashful personality.

"Senior Brother Ji," said Issei respectfully as he bowed slightly.

"So, how was this one month? Did your cultivation increase?" Sa Ji asked curiously as he approached the eleven years old body.

Shaking his head, Issei said, "No, but I improved a lot! I'm more knowledgeable in medicines and fighting!"

"Oh? Really?" Sa Ji said with a smirk, "So, how about a spar?"

"Spar?

"Yes, let's fight a little, I want to see just how good my junior brother is!"

Hearing his words, Issei thought over the situation. At the moment, he truly needed someone to spar with, specially a human. That was because during his stay there, he developed a fighting style, and he was eager to test it out.

"If that's so, then I'll have to trouble Senior Brother Ji."

"Great!" Sa Ji exclaimed happily. "Let's go the arena!" He then began to walk away, Issei following him behind.

In reality, the spar wasn't his idea. She ordered him to spar with Issei to see exactly how good he is and depending on how good he is, to register him in the medicine hunt. Obviously, Sa Ji tried to finish his task as soon as possible, asking Issei as soon as he met him.

Twenty minutes later, they were standing, apart by a couple of meters, on one of the various arenas of the school. The disciples were allowed access to the arena whenever they wanted, the only requirement was that it wasn't occupied.

There was a single rule – No killing. You could only kill on the Death Arena, the biggest arena in the area. Before battling in the Death Arena, both participants had to sign a contract that said that the school wouldn't be responsibility by their deaths.

"Junior Brother Issei, I'm going first!" Sa Ji exclaimed as he leaped forward and launched a punch at Issei. The punch was filled with spiritual power, it was the martial skill Heavenly Punch. A rank 3.

As Issei calmly watched the incoming strike, he simply straightened his fingers on his left hand. Just as the punch was about to hit its target, it seemed as if the world stopped moving.

In a swift movement, Issei analyzed Sa Ji's arms, its positioning and angle. Immediately, he stepped forward, calmly walking.

His movements were fluid, like a snake in water. As he walked, his left arm moved with unparallelled speed as it struck against three different areas on Sa Ji's arm.

Each step fluid, calm, beautiful and serene. Each strike wild, ferocious and fierce.

That movement encompassed Issei's true nature – serene but fierce.

The ultimate contradiction.

Not stopping, Issei continued walking, his arm moving like a whip as he consecutively struck various spots in Sa Ji's body – torso, legs and arms.

All that took less than one second.

When he finished, he was standing behind Sa Ji. At that moment, it seemed as if the world started moving again.

Before Sa Ji could even figure how Issei got behind him, he felt his entire body go numb as he fell to the ground.

"What the...?" Sa Ji muttered as he crashed against the ground. He couldn't move at all; it was as if his limbs weren't his.

"Senior Brother Ji, I think it's my victory," Issei said politely as he walked back to where Sa Ji was laying on the ground, an innocent and bashful smile on his face.

At that moment, Sa Ji understood. Issei had done something. Although he couldn't see, he understood that in that split-second, Issei had completely sealed his movement.

In Sa Ji's heart, the word scary appeared as he looked at the innocent looking bashful child in front of him. Truly frightening.

"Yes," Sa Ji finally said as he took in a deep breath, "Could you tell me what you did?"

At that moment, Issei showed a troubled expression, "I'm sorry, Senior Brother Ji, but I can't. It's a family secret..."

"Is that so?" Sa Ji said, slightly crest-fallen. He truly wondered what martial skill Issei used to beat him in less than a second.

Now, if Sa Ji were to find out that Issei hadn't used a martial skill, his reaction would have been priceless.

What Issei had done in reality was to use the method he developed after reading the books about human anatomy. By striking at specific points in a human's body, it was possible to restrain their movement and make they lose control of their limbs.

Obviously, such a thing couldn't be used in combat because no one had the eye-sight, mental power and speed necessary to do such a thing during a battle. It was simply impossible.

Once more, Issei was an exception. If it were the Issei from before, he wouldn't be able to do it. Although he could recognize the points he needed to apply pressure in a split-second, his physical body couldn't keep up.

That was before he fused with lightning. Because of the fusion, even while not in Lightning Incarnation state, his body had already improved by leaps and bounds. Although his physical strength only lightly improved, the speed in which he could move his limbs improved more than greatly, to the point where it could barely keep up with his mind.

Although it still wasn't fast enough to match his mind, he could still manage somethings, and applying pressure to certain spots was certainly one of them.

All of that enabled Issei to create his own martial art, one he dubbed the Strike Of The Lightning, because of the lightning-fast speed required to use the it.