"Training!!" (修業!!, Shugyō!!) is chapter 34 of the Boruto manga.
Naruto slides down the crater, explaining to Boruto he went through the trouble of not killing Delta so he could capture and interrogate her. Kawaki is startled by this, and urges Naruto to kill her while he still can. Delta's body begins to sound off, and Naruto jumps away, taking the children with him as it explodes. Kawaki points out that's the type of people in Kara. Delta's drone retreats, which Koji witnesses through his toad's eyes. He considers Naruto to be terrifyingly powerful, but still unable to defeat Jigen, and is sure that the key to Jigen's defeat is Boruto's Kāma. Naruto believes whoever worked on Kawaki before could restore him completely, but he has Katasuke work on him, limiting the repairs to the installation of a high performance hand, which would take a lot of time to prepare. Naruto asks about fitting Kawaki with one of the many prototypes developed for him, and Katasuke explains his creations only respond to the chakra of the person they're designed for. Naruto considers it for a moment, and has Katasuke fit Kawaki with one his prototypes anyway, and shunts off a bit of his chakra.
Boruto asks if the continuous drain won't be rough, but Naruto likens it to maintaining an active shadow clone, pointing out it'll be inactive when he's asleep. Kawaki asks if this is really ok, and Naruto points out this is a literal example of chakra being used to connect. Boruto comments on its coolness and jokes he wishes he had one. Kawaki asks if Boruto wants him to blow off his right arm, pointing out he could get rid of his Kāma. Boruto explains he was joking as Naruto and Katasuke laugh.
While going through data, Amado notices the arrival of Delta's drone, which connects to a terminal where two other Delta bodies are stored. He enters a few commands and one of the Delta bodies awakes, kicking open her containment and cursing at Naruto. Amado complains of her always breaking the lid of the containment, but she retorts that smashing things is her job and that if he has time to complain, he should do his job. He comments on her mouth. As she makes her way through the Kara base, Boro teases her over her defeat. Delta attempts to kick him, but her leg just goes through the projection. She assures him she'll be the one to kill the Hokage, but Code disagrees, saying he or Boro should do it, considering her to be outmatched. Delta refuses, saying she'll never feel right unless she kills them herself, but Jigen silences the discussion. He asks about Koji, who he put in charge of the mission. She explains he's concealed in Konohagakure, watching over Kawaki. Boro questions what Koji is doing, as the mission was to retrieve Kawaki before he even got picked up by the village. Delta agrees this was her original intent, but that Koji stopped her and let things play out to acquire more information. Jigen thinks it over. She reveals there's another Kāma wielder beyond himself and Kawaki, much to everyone's surprise. Code says they inspected the Hokage after Momoshiki's death, and asks if the new wielder is Sasuke. She explains it's Boruto, the Hokage's son, adding she saw Boruto's Kāma resonating with Kawaki's, assuring her of its legitimacy. Jigen considers it was Momoshiki's final act, making Boruto a vessel of his own. Amado watches him silently.
At Naruto's home, Kawaki asks why Naruto is doing so much for him. Naruto explains some chakra for his hand is hardly anything considering Kawaki shielded him and Himawari, and Kawaki retorts he's the reason they were attacked in the first place. Naruto just says Kawaki reminds him of himself from long ago and he couldn't let it go. Kawaki asks Naruto to teach him ninjutsu, who agrees. Boruto tells Kawaki he won't lose to him. Kawaki responds he should be the one telling that to Boruto. At night, Kawaki begins putting Himawari's vase back together. Kawaki gets his first Extreme: Shinobi Picture Scrolls pack with Boruto, Shikadai, and Inojin, and lucks out with a super rare card of the Fourth Hokage. Sarada comments to Mitsuki and Chōchō they got comfortable with each other fast, which Mitsuki attributes to him saving Himawari. Chōchō crushes on Kawaki. Kawaki comments on Minato also being a Hokage, and Inojin and Shikadai explain that Minato is Boruto's grandfather. Boruto complains about getting another duplicate card of his father, and Kawaki offers to trade his Fourth Hokage card, as he knows nothing about him and doesn't mind. Boruto celebrates his first, non-Naruto Hokage card. Kawaki ponders about Naruto. Over the next days, Kawaki begins training ninjutsu, and continues to put Himawari's vase back together. When he finishes it, he pours water to fill it up, but it leaks. He thinks there's a missing piece, but finds none left to add. He moves to go look for it, but Kurama manifests its head from a sleeping Naruto, telling Kawaki not to wander off from Naruto on his own.