There was no doubt that Black Zetsu had never truly been on anyone's side. Madara Uchiha, Obito, Nagato—they had all been pawns for him to use!
He had only ever had one goal: to resurrect his mother, Kaguya Otsutsuki.
But to resurrect Kaguya Otsutsuki, he first needed to create a "vessel" that could contain her will.
In the Shinobi World, the only way to create such a vessel was to use Kaguya Otsutsuki's bloodline descendants to revive the Ten-Tails, complete the Infinite Tsukuyomi Plan, and gather all the Chakra scattered throughout the Shinobi World into a single person. That person would then be raised to Six Paths level, and Kaguya Otsutsuki would be resurrected through their body.
In the original timeline, Madara Uchiha had been the perfect candidate for Black Zetsu's needs.
So Black Zetsu had disguised himself as a product of Madara Uchiha's will and assisted him every step of the way. Then, after Madara became the Ten-Tails Jinchuriki and cast the Infinite Tsukuyomi, Black Zetsu had struck, taking advantage of Madara's body—a vessel who had only just reached Six Paths level and couldn't yet resist Kaguya Otsutsuki's will—to successfully resurrect her!
In this timeline, Black Zetsu had originally been following the plan as well. But Shinji's sudden appearance had thrown everything into disarray. He had not only stolen the Ten-Tails, but also the pair of Rinnegan Madara Uchiha had entrusted to Nagato, forcing Black Zetsu to find another target.
By rights, Shinji, a descendant of Kaguya Otsutsuki, was undoubtedly the best candidate. But Black Zetsu had realized that Shinji was extremely cautious, and he had no chance of getting close. So he had no choice but to settle for the next best thing and target Ōtsutsuki Isshiki, whom Shinji had suppressed.
Before making his move, he hadn't been