Boruto: Naruto Next Generations' latest chapter makes a big revelation: the true power potential of the Karma seal. During the Kara Arc we learned that Karma was a means of the Otsutsuki marking their intended vessels for resurrection; the mark essentially "downloads" the essence of an Otsutstuki into a new body to help the evil aliens cheat death. However, after the death of Isshiki Otsutsuki and the end of the Kara Arc, it was made clear by Kara scientist Amado that Karma is still a powerful weapon - even without an Otsutsuki connected to it. In Boruto Chapter 63, we learn just what the power potential of the Karma seal truly is...
(Warning! Boruto 63 SPOILERS Follow!)
In the latest chapter of Boruto's manga, Kawaki and Boruto come face-to-face with Code, Isshiki's failed vessel and devoted disciple. Code's powers are frighteningly powerful enough to make him every bit the threat that Kawaki warned about. As it turns out, however, Kawaki's intent is not to battle Code: he is there to surrender.
Kawaki is smart enough to deduce that Code is working on behalf of someone else - even if he doesn't know that person is Ada, another one of Kara's psychotic cyborg creations. Kawaki's theory is that Code's handler actually wants to meet him (Ada indeed has a schoolgirl crush), and he's willing to submit to that review. However, Boruto successfully tracks Kawaki (despite his new chakra-stealth technique) and refuses to let his "bro" surrender to the enemy.
Boruto actually does battle with Code, despite the clear dangers, and it turns out to be as futile an attempt as Kawaki warned it would be. It's during Boruto and Code's duel that the Kara cyborg reveals to Boruto that he's only scratching the surface of Karma's power:
"You're an amateur when it comes to Karma," Code tells Boruto. "Do you know why you get drastically stronger when you activate Karma? Increased power and speed from improved physical ability is certainly a major factor, but that alone wouldn't result in such an exponential jump in battle strength. The real reason lies elsewhere. With Karma's true essence. Which is that the Otsutsuki's combat experience accumulated over millennia gets overlaid upon your own mind and body. That's why you get stronger.
In short, you instantly become a seasoned warrior. IF you're able to draw on Karma properly, that is."
This update on Karma's power is actually pivotal to the larger mythos Boruto has established. The series opened with the still ominous flash-forward of a teenaged Boruto and Kawaki battling over the ruins of Hidden Leaf using their Karma seal powers. Now we have grounds establishing that those powers don't at all need the corruption of an Otsutsuki ghost to be accessed; Kawaki and Boruto are uniquely suited to be shinobi whose powers are unlike any others. Just like Naruto and Sasuke before them.