The weekdays came, and Sona returned to the human world.
Rias was the same, but even though her plan had gone foil due to Serafall's interference, she didn't show a vexed expression. Instead, she appeared to be thoughtful, as if she was deep in thought.
Naturally, there was someone who was reluctant, but it was impossible for her to show it and just keep it inside her heart.
Still, when they were gone, he spent his time with his peerage members, giving them rewards, which they enjoyed so much.
Yet, why did Ravel keep staring at him with a weird gaze?
However, Riser decided not to overthink and visited the Sitri House as Serafall had promised to let him read all the information, research, and various data about magic and phenomena in the world collected by the Sitri House.
His job as an architect was already over, and he could easily spend his time mooching his wife's family.
Still, as a good husband, he thought he should give something in exchange, so he promised to set up a good "Fengsui" for the hospitals owned by the Sitri family.
Frankly, he could add the design, too, but if he gave everything so easily, no one would appreciate it. Instead, he should give them slowly as they slowly realize the benefit they could get from him, so they would eagerly give their everything to him.
This is the art of mooching!
Still, he felt that everything was great after he married Sona.
As expected, the benefit of having a strong sister-in-law was good.
While he was studying at the Sitri house, the others weren't free as they were busy on their own, especially learning the firearm magics he had just taught them.
As for Serafall, she still needed to do her job, so she could only leave him reluctantly.
Riser also didn't mind, and no one stopped him from stealing all the data that had been collected by the Sitri family for an entire generation, which made his mood great.
Nevertheless, the Sitri family also didn't mind telling him since most of their data was quite useless to him.
Sitri House was proficient in water magic, and Phenex House was proficient in fire and wind magic.
Frankly, he wasn't even sure what he could learn since he also didn't think it was necessary to learn all the knowledge of the Sitri family when he had a system.
Moreover, his ability in fire manipulation was enough to support him.
Lastly, even Issei, who didn't even train in magic, could become so powerful, so wasn't learning magic itself meaningless?
If he had to answer that question, then it would be dependent.
Everyone's situation was different.
If Issei could become stronger by an Oppai, it didn't mean the others could do that.
However, for him, who had a system, this was meaningless.
Still, it might be meaningless for him, but it was different for his peerage members.
His purpose wasn't because of himself but for his peerage members and also Sona.
He had mooched his family, so while he also helped her family's hospital with his "Fengshui" service, he thought he should help her become stronger.
Nevertheless, there was a massive difference between the ability of the devil and magic.
The ability of the devils was different from each other, and they were inherited, depending on which families they came from.
For Sona, it was water manipulation.
As long as it was related to water, she could manipulate it as she would.
It was the same case as him, who could manipulate fire and wind.
As long as he could imagine it, he could do anything with fire and wind.
It was also the case with Issei, who could use perverted power by using Oppai.
However, the magic was different.
Magic needs a formula.
When you do this, it will lead to this result.
Everything has been calculated.
This is what magic is.
It was complicated, and only those who were smart could learn it.
This was why Issei had never learned magic and only learned his Demonic Power, which could be used with his imagination since he wasn't smart enough.
Moreover, with how complicated magic was, this was also the reason why a devil made a contract with a magician. By making a contract with a magician, the devil could get all the data about magic so they could become stronger or apply it to the Underworld.
The development of energy by using a Magic Power that existed in the air was probably due to the research of a certain magician or even a devil.
Riser wasn't sure who this person was, but he knew that this person definitely got a lot of money through a patent.
Riser suddenly rubbed his chin and realized that using magic and selling the patent could make a magician rich.
So, the devil who invested in them with a contract is a venture investor?
Riser couldn't help but chuckle, but then he couldn't help but show an interest in the data about the field of the Rating Game.
'Hmm...'
[Your mother-in-law will come soon. There will only be you two in this room, and you can use this chance to deepen the relationship between you two by making her drunk, then—]
Riser stopped reading the system and decided to focus on his research.
The field for the "Rating Game" was something special, and managing the field was also how Ajuka Beelzebub got his money.
Yet, Ajuka didn't monopolize this knowledge and gave it to the other Maous and aristocratic families with great influence.
However, even if Ajuka gave this knowledge, it didn't mean they could use it.
As Riser had said before, magic was complicated, and this paper explained how the field was created.
According to the paper, the field was created on the basis of a certain Longinus, Innovate Clear.
Innovate Clear had the ability to create an artificial pocket universe that could create and support life. However, anything created there can only live in that universe.
By using that idea, Ajuka brought the idea of creating an artificial pocket universe as a field for the "Rating Game."
However, while this magic was used as a field for the "Rating Game," it could be used as a place for training.
Using an artificial pocket universe as a place for training could bring great convenience as there was no need for them to feel afraid their secret would be known or cause a nuisance to the surroundings due to their techniques.
Especially when most of his techniques included an explosion.
Yet, he was also helpless since his specialty was on fire, so if he didn't use an explosion, what would he use?
As he learned this knowledge, suddenly, a voice woke him up.
"Riser-chan? Are you still busy now?"
"Ah, mother-in-law."
He was surprised when he saw his mother-in-law was so close.
"Geez, I have called you several times, yet you ignore me..." Lady Sitri sighed as she pouted.
"........"
What should he do?
Sona, you need to come back, or else your husband was afraid that he might make a great mistake.
Nevertheless, facing this charming mother-in-law, he didn't lose his calm.
"How about taking a rest? You have been spending a day in this room."
"Huh? Really?"
"Geez, is studying those papers so much more fun than talking with your mother-in-law?"
Lady Sitri stared at her son-in-law with a gaze that wasn't like that of a mother-in-law.
"...."
Riser hoped that he didn't make a mistake.