The battle with Isshiki Otsutsuki appeared to be one of the deadliest. It pushed Naruto to his limits, and even though he acquired the Baryon Mode, it still seemed that it wouldn’t be enough. Isshiki was dominating the fight, and it appeared that it was just a matter of time before someone died. Most fans were expecting that this was going to be Naruto’s final fight, and he won’t be able to save Kawaki from becoming Isshiki’s vessel. However, Kawaki’s quick thinking and his devotion to Naruto resulted in an unexpected turn around that finally won them the battle.
In the previous chapter, Isshiki had teleported himself to a secret space-time dimension by latching onto Kawaki’s chakra signature. Isshiki realizes that he needs to make Kawaki his vessel again since his life essence is depleting. But Sasuke’s intervention helps the boy to flee. Isshiki is angered by Sasuke and Naruto’s constant intervention, and he beats them down. Kawaki is horrified by what is happening around him and his memories with his adoptive dad and years of abuse come rushing back to him. Isshiki, aware of how little time he has, call out Kawaki. He knows that Naruto means a lot to him, so he threatens to kill him if he won’t show up.
Sasuke and Naruto constantly urge him not to listen to Isshiki and run for his life. But Kawaki remembers what Naruto has done for him all these years. Kawaki does not wish to live in a world without compassion, and he surrenders in front of Isshiki, who is quick to put the rebirth mark on him once more. Whatever the shinobi squad has done so far starts crumbling, and Isshiki is happy that Kawaki will soon be in his most powerful and perfect form.
But Isshiki soon realizes that he has made a huge mistake. He realized that he couldn’t feel the connection of the work, which only meant one thing. It wasn’t the real Kawaki that he put his rebirth mark on. Kawaki used the doppelgänger technique to trick everyone. As Isshiki falls to his knees, Kawaki emerges atop a rock, and he stomps Isshiki, killing him for good.
Naruto and Sasuke are surprised by what they saw, as they had never expected that Kawaki would do something like that. Kawaki tells them that he is yet to master the jutsu since it took all his energy to do it. Isshiki had laughed at his ambition of becoming a Konoha shinobi, and ironically it was Kawaki who put an end to him. Naruto is overjoyed to realize that he has another trainee and son. Now that Isshiki is dead, the heroes can now focus on destroying the Kara terrorist cell.
Source: Boruto: Kawaki Outsmarts Isshiki