Chapter 148: The Hidden Crisis
As the Auswählen progressed, Yhwach, the ancestor of the quincies, gradually recovered all his strength. Since he led the quincy masters to attack the Soul Society thousands of years ago, he will attack Soul Society again without a doubt.
The Ishida family is a quincy family, and Soken was once a member of the Sternritters, so he knows a lot of things. He knows better than anyone else, the quincies' blind faith in Yhwach, and hatred for shinigami and the Soul Society.
The reason why they are still hiding now is just because they are not ready for war. Once the war starts that have been planned for a thousand years, the unaware Soul Society will never be able to resist the quincy's revenge if it is not on guard. As for why Soken is willing to tell Mazuru and Aizen about these things.
One is because after walking on the edge of death, he let go of many stubbornness in his heart.
The second is to protect everything he can and wants to protect.
When his grandson Uryuu asked him why his father gave up the glory of quincy for earning money, his answer was: "The things people want to protect are different, so relative disputes might arise for it. One day you will understand, and when you do, you should be able to understand what you really want to protect."
Uryuu didn't understand his father at that time. But Soken, as Ryuken's father, how could he not understand what Ryuken cares about was never money, but the people around him.
Kanae and Masaki obviously did nothing wrong, but they died one after another because of the Auswählen. How can Ryuken let go of this matter easily, after learning the truth, it is understandable that he would hate Yhwach, and the power of the quincy master itself. Similarly, his grandson Uryuu saw hollows' havoc in the world of living very early on, and wanted to protect the human beings, so he didn't mind teaching Uryuu the skills of quincy masters.
For Soken, the meaning of the quincy powers has never been for taking revenge on shinigami, nor to rule the three realms, but to protect the weak.
What the shinigami couldn't protect, the quincies will!
That's all!