Black Zetsu's misunderstanding
Encouraged by Eiko's concern, Kangetsu said again, "Have we reached the camp? That's good! Mother, take me back to my tent and call for Yamanaka In and Yamanaka Yang!"
After speaking, Kangetsu closed her eyes again, but this action brought tears to the Uchiha Eiko beside her. It was normal to lose one's sight due to overuse of the Mangekyo Sharingan. However, Uchiha Eiko still couldn't help but shed tears!
Uchiha Eiko looked at Uzumaki Mito beside her and said, "Thank you, Mito! I'll take care of Kangetsu's treatment now!"
As soon as she finished speaking, she disappeared. As for Uzumaki Mito, watching her departing figure, she felt a little worried. However, Uzumaki Suien beside her said, "It's alright, Mito. I reckon that kid Kangetsu is just blind; it's a side effect of the Mangekyo Sharingan. Kangetsu's body is definitely fine, but his strength will likely be greatly reduced!"
After Shui Yan finished speaking, it drew the ire of Uzumaki Mito, who immediately threw a punch at him and said, "Even if the Sharingan's power is gone, Kangetsu still has the Flying Thunder God. With the Flying Thunder God Technique in hand, who dares to underestimate Kangetsu!"
Having just obtained Asura's Chakra, his power increased exponentially, and Uzumaki Suien was directly sent flying by this attack!
This scene startled Black Zetsu, who had rushed over. He was startled not because Uzumaki Suien was sent flying, but because of the Chakra within Uzumaki Mito's body!
At this moment, Black Zetsu was Starba. Originally, Black Zetsu came to see Kangetsu, after all, Black Zetsu knew that Kangetsu had used the complete Susanoo, and at such a young age! Naturally, his eyes would lose their sight!
According to Black Zetsu's speculation, Kangetsu is half of Indra's reincarnation. Since half of his Chakra hasn't awakened, Kangetsu's Mangekyō Sharingan will gradually lose its light. And losing its light is not something Black Zetsu wants!
Black Zetsu wanted to turn those eyes into the Rinnegan, but what's the point of turning them if they're blind? That's why Black Zetsu came to heal Kangetsu. Because only the power of the Ten-Tails, or rather the power of the Six Paths, could restore Kangetsu's sight. And Black Zetsu, as the Otsutsuki Hagoromo, how could he not possess such power!
However, the moment Black Zetsu arrived and saw Uzumaki Mito, he was stunned again. At that moment, Black Zetsu clearly sensed a life force, a powerful life force Chakra, emerging from Uzumaki Mito's body!
Black Zetsu Chakra naturally recognized whose Chakra it was—it was Asura's Chakra! Although it wasn't much, he could confirm that it was indeed Asura's Chakra, and this Chakra was fused with Uzumaki Mito's —it wasn't given to Uzumaki Mito by someone else. So how could Black Zetsu not be shocked!
Actually, this is also Kangetsu's fault. In order to restore Uzumaki Mito, Kangetsu actually transferred a small part of the God Tree into Uzumaki Mito's body. With a small part of the God Tree, Uzumaki Mito also obtained Asura's Chakra, and now they have become one.