Start by Eating Jake Jake no Mi

While Masa had been busy with many things, naturally, he didn't forget to cure his aunt's sleeping disease. 

Due to the new development ability of Jake Jake no Mi, which allowed Masa of One Piece to put one more Devil Fruit into his body, this allowed him, Masa of DxD, to use the ability of Shiku Shiku no Mi, which Masa of One Piece gained from Doc Q. 

Still, while at this moment, Masa could use Shiku Shiku no Mi if he wished to, he could change it to something else later, depending on his wish, and this also made him wonder whether it was impossible to pull out the Devil Fruit that he had eaten. 

Jake Jake no Mi; Ton Ton no Mi; Pika Pika no Mi; Neko Neko no Mi, Model: Nemean Lion; Yami Yami no Mi; Baku Baku no Mi; Gasha Gasha no Mi; and lastly, Wapu Wapu no Mi. 

With four of Masa and Blackbeard's DNA, Masa of One Piece could eat eight Devil Fruits, and all of the slots were filled, but with the power of Jake Jake no Mi, he had one more slot, which could be filled with a Devil Fruit, but unlike others, this power could be changed into anything depending on their needs. 

Naturally, this Shiku Shiku no Mi was one that Masa of DxD needed at this moment. 

Sleeping Disease. 

Masa might have explained it in the past, but it was a disease that happened to the devils all of a sudden, and even now, the cause and the medicine or treatment of this disease haven't been found that caused the devil, whether they were common or noble, to sleep without being able to wake up no matter what until in the end, they were weakened and met their death. 

Even among all of the records that Masa had collected, including from those famous families that were good at research, they also hadn't found the answer to this disease. 

If one was caught by this disease, they could only stay alive by artificially maintaining their life in hospital.

However, Masa had found a way to wake up those who had this disease from the devil, but it was only for the House of Vapula and those devils with a power that manipulated a certain creature. 

While this was a good method, it could only save a few devils and was limited to those devils with the innate ability to control, but it didn't mean this method had completely cured the sickness. 

Instead, the disease still lay on the body, and if someone didn't awaken those who received this disease for a while, the disease would resurface, and they wouldn't be able to wake up. 

Frankly, Masa couldn't say that this disease was dangerous as it only caused people to fall asleep, but what made it dangerous was the fact that it could attack anyone, and no matter who they were, they would be defeated by this disease. 

Or rather, no matter how strong the creature was, it was impossible to defeat a disease. 

Even in the world of One Piece, Gol D. Roger, who was known as "the King of Pirates," and Whitebeard, who was known as the "Strongest Man in the World," were also powerless against a disease. 

So, knowing this, while Masa knew that it might be dirty, instead of trying to solve this disease, he thought of using this disease as a way to take down his opponents! 

While the devils' opponents were the angels and the fallen angels, it didn't mean that all the devils were kind to each other. Instead, many conflicts happened between all devils, like how a human, even though all of them were the same, fought, whether it was due to language, country, color, or even to the smallest things. 

However, as they were all devils, it was impossible for Masa to kill them, at least openly. Taking care of the aftermath of this problem was even more difficult, especially for him, who had great ambition within him. 

The price he had to pay to kill someone he didn't like, especially in the Underworld, was huge, so it was troublesome. 

Yet, while Masa understood that, some braindead didn't understand that, and even if they knew that he was dangerous, they tried to fight him, provoke him, and do something stupid to hinder him. 

Naturally, this was the same case with the other Masa, but since he had gained the Shiku Shiku no Mi, he couldn't help but stop his happiness, especially when he could use this ability to attack someone without being noticed, dirtying his hands, or worrying about the troublesome aftermath. 

Especially if Masa could gain the virus of the Sleeping Disease and record it on the Shiku Shiku no Mi. 

If his enemy suddenly got a "Sleeping Disease," then what would happen? 

'Hehehehe...' 

Or rather, not only Masa of DxD, but this sleeping disease was also useful to all other Masa to take down their opponents. After all, if their opponents continued to sleep for an eternity, what could they do, then? 

Still, the most important thing is that no one would expect that Masa was the cause of his target being caught by the sleeping disease! 

Somehow, Masa also understood why Chopper hated and tried to reprimand those who used disease as a weapon, and if Masa couldn't get this Shiku Shiku no Mi, then he would also disdain someone who used such a dirty method. 

Yet, Masa, who had gained the ability of Shiku Shiku no Mi, knew that there was no need for him to hesitate, so he quickly got his aunt, Misla Bael, who had a "Sleeping Disease." 

"Do you still want to continue with the research to cure the Sleeping Disease, Masa?" Misla asked after Masa pulled her to one of his laboratories. Still, even if it was his laboratory, it wasn't much different from a cozy room, as Masa didn't want to make her nervous. 

Yet, even so, she was nervous, but it definitely had nothing to do with the fact that Masa wanted to ask for her blood for research. 

"Yes." 

"But, blood, huh? Aren't you afraid that you will be caught by this disease?" Misla asked her nephew who had grown up. Despite being young, he was a man who would be responsible for his women, causing many to fall for him due to his traits. 

"It's fine. I don't know whether I can find a cure for this disease, but I want to try." 

It was impossible for Masa to tell the truth that he could cure the disease directly with the Shiku Shiku no Mi, nor did he plan to tell his aunt about his plan to use the "Sleeping Disease" as a biological weapon.

After all, unlike him, who was a selfish and emotionless bastard, the women and all the devils on his side probably would feel frightened by his idea to use the "Sleeping Disease" as a weapon, and their view of him would change. 

While Masa didn't care about their view, he wanted to keep this ability to manipulate a disease as a trump card that no one knew so that way when many of his enemies fell asleep and then died, no one would blame him. 

However, as Masa was eager to get Misla's blood, his aunt's reaction caused him to be dumbfounded since after he said those words, she started to undress, showing her mature yet lewd body that was hidden within the neat dress that made her appear like a good wife. 

The moment the rawness of her body was only limitedly covered by her undergarments, Masa couldn't say anything and just remained in silence until Misla asked with a slightly mischievous expression, "Do you want me to take off my undergarments, too?" 

"..." 

"...ah, um." 

Masa was being honest before he quickly realized what he had said, "Ah, no, put your clothes on, Aunt!"