WARNING: The following contains spoilers for Boruto: Naruto Next Generations Episode 218, "Partner," now streaming on Crunchyroll.
The Boruto anime has been very unforgiving to Konoha's shinobi recently as Isshiki finally unleashed his Ōtsutsuki form. The alien's been taken to a secret dimension but while Naruto, Boruto and Sasuke hoped to contain him there, Isshiki runs rings around them, even staving off Naruto's incredible Baryon Mode. However, thanks to some quick thinking, the villain is finally defeated -- thanks to Kawaki improvising with Naruto's most underrated move.
When Isshiki grabs Kawaki as the dust clears, he taunts the teen for how he couldn't evade his eventual fate. He admits Naruto wrecked his body, but now Kawaki will be rewritten using Isshiki's DNA, crafting the perfect vessel. It's why he created Kara in the first place and at last, Isshiki's getting the host he needs to conquer the world with the Ten Tails and the God Tree.
However, as Isshiki's body crumbles, he senses something is off with Kawaki as he tries to restart the process to get a sacrifice so he can create the chakra fruit. The marks of Kawaki's Karma fade, leaving the villain coughing up blood and dropping to his knees. Shockingly, the real Kawaki emerges atop a cliff, confirming Isshiki had been tricked with a shadow clone.
Even Naruto, bloody and barely able to move, is stunned because it takes a lot of chakra manipulation to create the perfect clone using the "Kage Bunshin No Jutsu" technique. With Isshiki duped and time officially expired, Kawaki leaps off the cliff and stomps the tyrant to ash, gloating about how his former master never should have underestimated him.
It's quite remarkable as this is the move the Hokage taught him -- something many shinobi from the Hidden Leaf, such as Kakashi, Jiraiya, Minato and Naruto's predecessors, tried to perfect. Naruto honed it for years in his own series, using Kage Bunshin No Jutsu to beat the likes of Sasuke, Kaguya and the Uchiha traitors from time to time. Many fans don't think it's a big weapon in his arsenal, admittedly, but the way he uses it for misdirection, to sneak up on people and to share chakra to others has made it quite effective.
Now in Boruto, Kawaki has topped Naruto and not even Isshiki's all-seeing Byakugan could spot the ruse. It even deceived the Konoha-nin, so clearly Kawaki has serious talent. It may be due to his own alien physiology and his different chakra flow as well, which leaves fans wondering what else he could elevate once he learns more from his friends.
Ultimately, it's perfect karma as this death blow comes from Isshiki's former slave, Konoha and from the leader he almost killed to get his way. As the liberated Kawaki rushes over to help Naruto, he will finally get the chance at family that Isshiki never offered.