To summarize, the three stages of the Fusion Equation.
Stage One: Fusion energy attack.
Stage Two: The essence of fusion energy, granting oneself power at the level of Transcendents.
Stage Three: The essence of fusion life, allowing one to truly step into the realm of Transcendents.
Although the third stage of fusion is powerful, experimental data on life-form fusion is still too scarce; many things remain at the theoretical stage.
Sirzechs is a good subject; by having him constantly switch between a devil and his Devils True Form to observe the changes, good data can be obtained.
However, constantly switching between these two states is no small burden for Sirzechs.
Moreover, Sirzechs is too busy; after all, he is a Devil King.
Aside from that, Rias is preparing to intercept Naberius's experimental materials for artificial Transcendents.
Along the way, she can take those two kittens, Toujou Koneko and Toujou Kuroka, under her wing and pet them every day~
Even so, there is still a massive lack of data required for the experiment. If she followed her plan and played by the rules, it would take at least ten years to reach this step.
If she had a spiritual wish-granting machine like the Hōgyoku, this process could perhaps be shortened to two years!
Not just the third stage—the Hōgyoku also holds great value for her Hakai Hōteishiki, estimated to speed up her growth by more than ten times!
This is already quite a remarkable thing~
Unohana Retsu: "From my position, it is difficult to obtain such a thing."
It wasn't just that she couldn't get it; Unohana Retsu's position didn't support it either.
Unohana Retsu is a Captain of the Gotei 13, belonging to the side of order.
Additionally, Yamamoto Genryūsai Shigekuni has never truly trusted her, and to some extent, he even monitors her.
Therefore, it is difficult for Unohana Retsu to do certain things; after all, her Zanpakutō is not Mirror Flower Water Moon.
"I can go to your world; that way, your involvement can be cleared."
Rias: "Of course, I can't guarantee I won't cause trouble. At most, I can promise I will never intentionally destroy order. Whether to trade is up to you."
"It's just that something like the Hōgyoku is of high value to me now, comparable to a 'nine' on a scale of ten. In seven or eight years, once my Fusion Equation is refined to a certain extent, its value will drop from nine to a number smaller than one."
"I must remind you that the value of the Hōgyoku will decrease over time."
Unohana Retsu: "Let me consider it."
"There is one more thing."
Rias: "I have an item here called Devil Chess Piece, which can transform other races into devils, with forms determined by Western chess."
"1 King, 1 Queen, 2 Rooks, 2 Knights, 2 Bishops, and 8 Pawns—16 pieces in total."
"Among them, the King Piece can increase one's strength by dozens or even hundreds of times. Even for you, it could provide at least a tenfold increase."
"I can provide you with a Shinigami version of the Devil Chess Piece."
"In exchange, I need Kido (Spirit Path), Return, and a large number of Asauchi to reverse-engineer the manufacturing method of the Zanpakutō."
Asauchi are the prototypes of Zanpakutō, and for Unohana Retsu, they are easy to get her hands on because they are basic items.
But getting a large quantity is not easy.
Because Zanpakutō are composed of souls, it's not that easy to analyze and convert them into one's own system; a large number of Zanpakutō are needed for experimentation.
But for Rias, such a thing might be very valuable.
A Zanpakutō's shape, state, and abilities are forged using the Shinigami's own soul as a prototype. Shinigamis gain power by learning the name of the Zanpakutō given to them and engaging in a mental dialogue with it.
If one reaches Aizen's level, merging the Zanpakutō with oneself, perhaps the second stage of the Fusion Equation could be completed through a shortcut.
Unohana Retsu: "The reason you could reach this level at your age is because you used that kind of piece?"
"No~"
Rias smiled and said, "Although the manufacturing technique for the King Piece has been deduced, I haven't had the chance to use it yet."
King Pieces do not exist in the Underworld; they are more like urban legends.
But without a doubt, Ajuka has the ability to manufacture them; he simply destroyed the manufacturing technology for the King Pieces.
However—
As long as she understands the manufacturing method of Devil Chess Piece, Rias herself can manufacture a King Piece.
Because she possesses a method to extract high-purity crystalline substances—the Fusion Equation!
In fact, the finished product is almost ready.
It just so happened to be right before joining the Chat Group!
If she wanted to, she could cross the boundary to a Devil King at any time through the Devil Chess Piece.
Although it won't allow her to complete the second stage of the Fusion Equation, an increase in demonic power is also a good thing.
It must also be said that the relationship between Ajuka and Sirzechs is truly excellent; due to his close relationship with Sirzechs, Rias can obtain most of what she wants, including technology that is a top secret in the Underworld.
Of course, something as significant as the King Piece's manufacturing method was entirely deduced by Rias herself.
"Very well. Shinigami skills are easy to provide, but providing a large number of Asauchi is somewhat difficult."
Unohana Retsu: "I can provide ten Asauchi at most. Any more, and the Gotei 13 will notice something is wrong."
"Alright, let's leave it at that then."
Rias thought about it and realized there was indeed no need to make things difficult for Unohana Retsu.
The prototype of a Zanpakutō is an Asauchi, and the raw material for an Asauchi is a soul.
A Shinigami eats and sleeps with their 'Asauchi', and through accumulated training, they write the essence of their soul into the 'Asauchi' to create 'their own Zanpakutō'.
Perhaps Rias wouldn't need too much modification to directly integrate it into her own system.
But wanting to reverse-engineer it and deduce the forging method of the Zanpakutō would be somewhat difficult.
Ten Asauchi, as precious experimental subjects, are a bit few in number.
She would just have to be careful during the experiments and try not to destroy the Asauchi.
Wait, there seems to be another way.
The Arena projects one's own power, including weapons. This can be confirmed by the fact that Rias's Heavy particle destruction missile and Unohana Retsu's Zanpakutō were projected.
If the Arena is opened, studying Asauchi within the Arena means nothing would happen even if they were destroyed; instead, valuable experimental data could be gathered.
Rias: "You only need to provide two Asauchi. One for use, and one for experimentation."
"But in exchange, I need you to open the Arena with me and conduct experiments in the Arena until I have fully mastered the knowledge related to the Zanpakutō."
Unohana Retsu: "Fine."
The Arena has several modes.
Duel mode, group mode, teammate mode, etc., but notably, there is no solo mode.
The reason for dragging Unohana Retsu into a two-person mode was entirely because of that Jibril; Rias was very worried about her head being quietly sliced off while she was conducting experiments, which would be far too grotesque.
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