Kakashi finally rescued Lin, but the cave was about to collapse. In order to save Kakashi, Detu's right body was crushed under the boulder. At the last moment of his life, Detu decided to give his left eye sharingan to Kakashi, which made Kakashi a "copy ninja" later.
When everyone thought that Detu was dead, in fact, Detu was not dead, but was saved by the spot, and the intercellular cells were used to help Detu recover.
However, Detu did not return to Muye Village because Detu saw Lin die at Kakashi's hands. Although Detu knew it wasn't Kakashi's fault, Detu was still dark and determined to make a world with Lin.
Everything is to create an infinite Harle. Before that, a lot of preparation is needed, and it is also important to strengthen the strength. Previously, Dai Tu transplanted his sharingan to Kakashi, and Dai Tu knew that double sharingan could exert the greatest power. So why didn't Dato get his sharingan back?
There is a deep relationship between Detu and Kakashi.
Both Detu and Kakashi are members of the Namikaze Minato team and apprentices of Namikaze Minato. Although they are always noisy at ordinary times, there is no denying the deep emotional bond between them, especially that they have experienced life and death together.
With this article, I will definitely not go to Kakashi to get sharingan back. After all, it's a gift for Kakashi.
If we go to saringen, we'll blow our cover.
Tuotu has always been an active spot. Although he has been wearing a mask, the sharingan he exposed is enough to prove it.
If you take soil to catch Saringan in Kakashi, it is very likely to be exposed, because Saringan with soil has almost the same ability as Kakashi, so it is very likely to expose his true identity.
To tell the truth, Tui actually has many opportunities to get back his sharingan, but Kakashi and Tui are so familiar after all. Once they fight, Kakashi is likely to recognize Tui, so isn't it worth the loss for Tui?
To sum up:
First, Tui and Kakashi have deep roots, and Tui will not bring sharingan.
Second, Kakashi and Detu are familiar with each other after all. If you use Detu, Kakashi will probably recognize Detu, so it will not be worth the loss.