Start by Eating Jake Jake no Mi

By using his "Archive" ability, which made him able to transfer the knowledge of ninjutsu to the heads of those who wanted to learn it, the learning progress of Kuroka, Serafall, Ravel, and Asia moved at an incredible speed. 

Ninjutsu, while it might not give them an advantage in direct battle, helped them a lot in sneak attacks or running away. 

No, it could be said that with the knowledge of ninjutsu, their survivability would increase further, especially with the magic known as "Matoi." 

"This is an incredible ability." 

Even as the strongest female devil, Serafall had to admit that "Matoi" had an incredible ability. 

To create a body double that would deceive everyone. 

If Masa had to say, this technique was like the reflection of the moon on the surface of the water. As long as they mastered "Matoi," they would become the moon, which was unreachable in space, and what was shown before everyone was just the reflection of their bodies, which was meaningless to attack, yet even so, everyone would attack this reflection, ignoring the real body of the user. 

Still, once again, if the opponent attacked them with a wide range of attacks, they would be hit, but even so, this ninjutsu was powerful. 

However, knowing this benefit, they also tried their best to collect all of the records and knowledge for Masa, whether it was from their family or bought with money. 

Any knowledge, all of it, no matter what the subject, was collected by Masa, and all of it was for his plan, "Index." 

At the same time, as Masa had said before, this knowledge could be good for their future descendants, which made them blush and work harder. 

Still, Misla also worked harder to teach Masa the necessary knowledge for his marriage life, which made him moved by her dedication. 

However, without a doubt, Serafall kept staring at him with a blank gaze, and Kuroka snickered at his naughtiness. 

Meanwhile, Asia was as obedient as ever, letting Masa teach her various knowledge to improve her skills, which made the two of them happy~! 

Still, sometimes, Masa wondered whether Ravel would ask him to break away from the engagement with everything that he had done, but—

"It's fine." 

"...it's fine?" 

"You are an exceptional man. It's normal for you to be surrounded by females. 

Rather, Ravel was generous in this area, especially when all of the women that Masa was with were exceptional, and no one was lower than the others. Whether they were strong, had a special status, or had unique abilities, all of them were special women, and he won their hearts fairly instead of forcing himself on them. 

Frankly, it was probably better for Masa not to marry at all, so that way, everything would be fair for everyone, but then again, the one who wished to marry him was Ravel, and even if he was like this, she didn't regret it. Instead, she felt that she hadn't chosen the wrong man due to how exceptional he was and how caring he was toward her. 

Masa might not have much loyalty or control over his lower body, but even so, the time they had spent together had made her fall in love with him, and even if he wasn't perfect, she wouldn't change her opinion and would definitely become his wife as her love toward him was so immense. 

Others wouldn't understand this feeling and probably thought that she was stupid for fighting for her love, yet who cares? 

Ravel was happy, and she wanted to be with him; that's enough, isn't it? 

Watching Ravel, who expressed his love toward him, Masa fell into silence, then kissed her lips, which she accepted happily, but somehow, with his nature, he became more naughty, pushing her softly as his hands started to touch the womanly parts of her body. 

"Masa..." 

With a bashful yet lewd expression on her face, Ravel softly called his name as she let out a comfortable sigh. 

The two might not have gone all the way, but all of them had done many things together, and when the two were official, they were sure they would go all out, especially when it was hard for a devil to get pregnant. 

Still, after Masa comforted Ravel, she also didn't forget to comfort him. 

Holding her soft, blonde hair tightly, Masa also sighed comfortably, thinking that his fiancee was as great as ever. 

Still, even if many things happened to him and everyone, Masa didn't forget about his study, especially about the Evil Piece, the special item that allowed other creatures to reincarnate as the devil, gaining their traits and power. 

This was an amazing thing, he thought, but then again, while it was amazing, he knew well that the creator of the Evil Piece, Ajuka Beelzebub, wasn't the original creator.

Instead, Ajuka created the Evil Piece from the special attribute crystals available on Agreas Island, the floating island that existed in the Underworld, which contained the technology of the Old Satans as the city hadn't been fully explored yet.

Frankly, Masa wished to go to Agreas Island to see that unexplored technology, wondering whether it could be used for everyone, especially for Masa of Mahouka, who planned to change everyone in his world into magicians to erase all the conflicts.

At the same time, Masa also wondered whether there was more mystery in this world. 

While it might be strange to say this, he felt like... this world was a new world. 

His words might be strange and confusing, but while it was just his hypothesis that an advanced civilization with great magic and science existed, somehow, it was destroyed due to the lack of energy, considering it was impossible to create energy out of nothing. 

By then, when the old world was destroyed, a new world was born, and this was the current world of the DxD, but even if that past world was destroyed, much of its technology remained on Earth. 

"Energy cannot be created or destroyed."

As Masa murmured those words, he felt a headache since he had to admit that even with four Masa, it was hard to reveal the secret behind everything in the universe. 

"If there was more Masa, that would be great," he thought. 

Nevertheless, even if he didn't have enough power to reveal everything in his current state, it was enough for him to live in this world, especially when he had mastered the power of Shiku Shiku no Mi, and as expected, he could spread this disease to the devils as he had used it on the criminals on his domain and other domains. 

At the same time, this disease could also affect other races, too, which was amazing, he thought. 

Yet, let's not make everything into a big deal and stay low-key.

However, when he was about to go to work in his office, he had never expected that he would meet trouble. 

On his way to the office, when Kuroka followed him, wishing to try to do it at his office, a voice was heard from the distance. 

"YOU BASTARD! GIVE ME MY BOOSTED GEAR!" 

Yet, at that moment, the young man quickly froze in place and was rooted in fear since everyone in this place quickly stared at him with killing intent for sullying their master.