Before long, Unohana Retsu had obtained books on Zanjutsu, Hakuda, Hohō, Kidō, and Return, as well as an Asauchi.
She sent them to Rias using the Chat Group's red envelope function. Rias responded, "To create pieces that match the characteristics of you Soul Reapers, a large amount of reishi is required."
"Since I don't have anything like reishi on my side, you need to use this device to collect enough of it."
After saying that, Rias sent a red envelope to Unohana Retsu.
Inside were ten Energy Collectors, each capable of gathering energy equivalent to that of a High-Class Devil.
These Energy Collectors were built using the power reactor inside Agreas as a model.
Compared to Agreas's power reactor, these collectors were quite simple and could be achieved with a standard Formula.
Unohana Retsu: "How do I use this?"
Rias: "There's a button in the middle. Pressing it will automatically absorb energy from the air. Try to see if it can absorb and store reishi."
Unohana Retsu: "It works."
"This process might take over ten days, so please wait patiently for a while."
Rias: "I also need to organize the grimoires Jibril sent over and then provide corresponding books in return. I might be a bit busy during this time."
Unohana Retsu: "No matter, our Soul Society is still stable."
Rias: "Mhm. Also, give the matter of the Hōgyoku some careful thought."
Unohana Retsu: "I will."
It wasn't that Unohana Retsu didn't want to agree; it was simply that Rias and Jibril were too dangerous.
As for the Arena, since it used projections, it didn't matter even if she died.
But she couldn't be certain what consequences would arise if Rias were to come to her world.
Jibril: "@Rias, I want some too!!"
Rias: "These pieces are ineffective for you. They can't provide you with a boost, nor can they convert other races into the Flugel. The level of technology isn't high enough yet."
"I see, then never mind~"
Jibril: "However, the corresponding technology is quite interesting. Can you trade with me?"
Rias: "I will give you a corresponding return gift based on the value of your grimoires."
Jibril: "Alright~"
After more than ten consecutive days, Rias finally finished organizing Jibril's grimoires and completed the grimoire trade with her.
Jibril's grimoires contained many high-level Magic Formulas; it was clear these had been plundered from other races.
For example, there were experimental magic Magic Formulas from the Forest Spirit Race.
Those were techniques constructed by the Forest Spirit Race and the Fairy Species to control the 'Core' of Fantasy Species.
If this technique functioned normally, it could manipulate the Giant Species, Fantasy Species, and even the Flugel.
The technique was so overly idealistic that Jibril mocked it relentlessly.
Even so, this technique held extremely high value.
If she hadn't joined the Chat Group, Jibril would have used the theory of this technique as a basis to overwrite her own techniques, creating a self-destruction that formed a triple-strike ultimate attack to hunt a Dragon-kin alone!
Even for Rias, this technique held considerable value.
"Finally finished organizing everything."
Rias wiped her forehead.
It wasn't just the grimoires Jibril sent; she also had to deal with her own.
She sorted out the useful books and made copies to facilitate future trades.
This had cost Rias a significant amount of effort.
Neither the Gremory Family nor Sirzechs would have imagined that the Demon King's sister had become a traitor to her race, using the knowledge of the Devil race for trade.
~
"The energy collection should be about done~"
Not long after, Unohana Retsu sent over the devices filled with reishi.
"Ten devices in total; I wonder if I can succeed on the first try."
Rias muttered as she stored the ten devices in a sub-space she had created, then flew toward the Gremory Family's training ground.
The training ground was also a Other World space Rias had opened; all the Magic Formulas were constructed by her own hand. Even the Demon King Ajuka would find it difficult to observe the interior of this Other World without alerting Rias.
Arriving at the training ground in the Other World, Rias took out an Energy Collector.
The main function of the Energy Collector was at the bottom, while the top was a glass dome made of a special material designed to contain energy.
It was similar to the Sekki-seki from the Soul Reaper world, capable of blocking energy.
The reason it could also block reishi was because magic power wasn't the only type of power in this world.
It should be said that magic power was a power unique to the Devil race.
The power of Angels and Fallen Angels was called the Power of Light, and the powers of other Pantheons each had their own names; they were essentially different energies.
Therefore, materials that blocked energy didn't just block magic power.
"Let's begin, then."
A geometric, three-dimensional magic circle was constructed in her hands, with calculations inscribed upon it; this was Rias's Fusion Equation.
This was an independent Equation belonging solely to Rias, derived from Demon King Ajuka's 'Kankara Formula'.
She opened the device, and a large amount of reishi was released from the transparent glass dome, only to be contained within Rias's technique.
The outermost layer of the Fusion Equation was an incredibly sturdy barrier.
This barrier was meant to prevent energy loss from causing a massive explosion—in other words, to block an energy burst.
The internal techniques consisted of small, three-dimensionally constructed square blocks that changed constantly like a Rubik's cube; this was a vital part of stabilizing the fusion.
The innermost part was a circle used to manipulate the fusion from a macroscopic direction, serving as the control console.
The three layers of techniques were densely packed and extremely complex, as beautiful and pleasing to the eye as a work of art.
"Energy Fusion—Begin!"
The technique began to operate, and the internal reishi started to collide under Rias's control.
The technique provided an environment similar to 'high pressure' for the internal energy, and it was extremely uniform and stable.
After several qualitative changes—releasing energy, absorbing energy, releasing energy, absorbing energy—and repeating this cycle several times, the reishi condensed into stable crystals under the influence of the technique.
"No accidents occurred. It seems that while the essence of the energy is different, there's no change in the fundamental elements."
Rias murmured as she picked up a crystal.
The crystal was sky-blue, rectangular in shape, and full of sharp edges; it looked very beautiful.
The interior seemed to sparkle and glow.
Yet no one could realize what kind of energy was contained within.
After countless purifications, it formed the raw material for creating King Pieces.
"Let's start manufacturing the King Piece."
She slightly modified the technology within the Devil Chess Piece, and soon, a piece in the shape of a king appeared.
Unlike the black and white of the Devil Chess Piece, this piece was sky-blue.
"No accidents happened."
Rias toyed with the piece for a while.
Because of the characteristics of reishi, this piece was more inclined toward the soul.
In other words, a Soul Piece.
Of course, calling it a Soul Reaper Piece was also fine~
The King was finished, and the other pieces were simple.
Soon, Rias had put together a full set of Soul Reaper Pieces.
Sending the Soul Reaper Pieces to Unohana Retsu, Rias said, "I've already sent you the control method. The pieces can be integrated or removed at any time. To avoid any accidents, let's open the Arena and experiment first."
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