In High School Dxd With Powers Of Nanatsu No Taizai

Ten years passed in an instant. However, contrary to Leo's expectation, nothing unusual had happened since the day Serafall appeared.

Since the appearance of Serafall for the first time, she had come back regularly to visit and with time, Leo got used to it. Every time she appeared, she always sought to play with him. And over his first three years, Serafall tried several ways to see if Leo could use dark matter at will or not.

When he turned six. Leo, who could not endure her persistence, a term used the dark matter, only for Serafall to become even more interested and ask him to know, what else he could do with it, which Leo accepted in exchange for her teaching him magic.

Along with the effort and time, Leo learned magic, the growth of his strength was good enough for someone who had never been in contact with magic.

Also, he discovered the difference between magic and devil energy and that using magic was not easy at all.

All this because devil power requires the power to use your imagination and the power to create, as well as having a good sense, while magic is only knowledge to control equations, that is, to use your head and do calculations. So while they may seem similar, they are very different from each other.

In addition to this, Serafall also told him about the various types of techniques such as:

The Youjutsu, which would be a unique skill only for Youkai that allows them to cast offensive and defensive spells. They also create and control illusions and produce a poisonous mist that is only effective against specific races such as Youkais and the devil.

The Touki is one that can be used by those who are trained in Senjutsu by creating an aura of life force that they will carry around their body, increasing their attack, defense and speed tremendously. Another method to obtain the Touki is to train the body to the most extreme limits, gaining control based on life itself. And it even allows the user to counter magic attacks.

…

Time never waits for anyone, while Leo was still practicing magic and trying to use a particular type, two years had passed and now he was twelve years old.

In the Tomika courtyard, you can see Leo holding a branch and Serafall on both sides of the courtyard.

"Are you ready? Leo-chan" Question Serafall

"¡Yes!" Responds Leo with determination.

listening to Leo, Serafall moves her hand and a ray appears. Once it appears, as if it had come to life, it heads for Leo.

"Full Counter" Leo shouts as he swings the branch toward the ray.

"It seems that I need to practice more to be able to dominate it completely" Murmurs Leo to himself.

"You don't need to shout Leo-chan. You can use the technique even if you don't." Explains Serafall.

"It's necessary. I cry out for the dreams and dėsɨrės of every man in the world" exclaims Leo proudly.

When Serafall listens to Leo, she rolls her eyes: "Okay, Leo-chan, now, what kind of magic is it that you used?"

"Jejeje, secret" Responds Leo with a smile

"Come on, don't be mean." Before Leo's refusal, Serafall begs her with tearful eyes.

(Really, who would think she would be so childish?)

"I'll tell you, but on one condition."

"What condition?" asks Serafall feeling suspicious.

"No." (You're just gonna cause trouble).

"I promise I won't cause any trouble," answered Leo as he moved the branch back and forth.

"It's not no, you know I can't take you. If Sirzechs-chan finds out, he'll do nothing but bother. And he'll try to stay with you, so I won't let you meet him."

"Are you afraid of Sirzechs? And I thought Nee-chan was the strongest" Sighs Leo with regret. "Since you say no. Then I will surrender," he says as he slowly begins to walk away.

The corners of Serafall's mouth contracted as she rolled her eyes again. "I know what you're trying to do Leo-chan. But it won't work, maybe I'll think about it if you offer me something else." Serafall replied with a cunning smile.

Leo, listening to Serafall, slowly turns around and looks at her with puppy eyes.

"I have nothing more to offer," Leo says with regret

"I'll take you if you show me what more you can do with dark matter," Serafall said with a business smile.

"All right,"

"Didn't you hear me well? I said I accept," repeated Leo with a smile.

"E, I mean..." She regained her composure and looked at Leo with a suspicious look. "Thinking better, I think I need to ask for more" I won't let you go so easily.

"The negotiations are over, I hope you don't go back to your words. Nee-chan."

Serafall: "..." (He played me)

"And then, when do we leave?" Leo asked ahead of time.

(Sigh. I seem to have no choice but to carry him) "In a month I will go to the underworld. I'll tell you when to get ready."

"All right." Stopping to think for a moment, Leo adds, "Since you want me to teach you what else I can do with dark matter, I'll need an opponent to fight. So if Nee-chan can find one I will gladly teach you."

"Then this was your plan," Serafall says with a smile that is not a smile.

"I don't know what plan you're talking about Nee-chan" Leo replied with an innocent smile.