WARNING: The following contains major spoilers for Boruto: Naruto Next Generations #43 by Masashi Kishimoto, Mikio Ikemoto and Ukyo Kodachi, available in English from Viz Media now.
The Boruto manga has seen Naruto's son in a state of desperation as he attempts to save the Hokage from the clutches of Kara. The terrorist cell is holding Konoha's leader prisoner in a secret dimension, leading to Boruto and Team 7 battling Boro to free him.
Luckily, they're able to rescue Naruto from the jar in which he was placed by Jigen, Kara's leader. But in the heat of the moment, the possessed boy just made a move that could leave his dad open to corruption by one of the franchise's nastiest villains.
Naruto finds the going tough in the Boruto solo film when he has to protect his kid from Momoshiki Ōtsutsuki and his lackey, Kinshiki. They eventually overcome the odds, with Boruto killing Momoshiki who wreaked havoc in the wake of Kaguya. However, Momoshiki leaves a Karma mark on Boruto, which means that he'll return one day and try to use him as his vessel. Well, that day has finally arrived, and it's a brutal affair.
Chapter #43 finds Boruto and Kawaki realizing that if they combine their Karma marks, as they can manipulate space and time, they should be able to pull Naruto out the jar. So said, so done, but Naruto's unconscious after Jigen leaves him near death. His chakra levels are surprisingly low and this leads to Boro coming in for the kill, enraged that he failed his mission.
At this point, after a severe beatdown, Boruto turns into his alien persona and Momoshiki uses the boy's body to pummel Boro and prove who's the strongest ninja around. But Boruto's chakra level is so low that Momoshiki takes the levitating kid down and touches Naruto, absorbing his unique chakra. This levels Boruto up, and he kills Boro with a super-Rasengan, only to snap back to reality and take control of his body again.
Now, while the day has been saved, this could have dire consequences for a couple of reasons. Firstly, we don't know if Momoshiki transferred some of his essence to Naruto, which could lead to a Karma mark on the veteran. Also, chakra-lending is a gateway, so flow can occur two ways, in and out. That means that if Momoshiki wanted to, he could also have placed a mark on the Nine Tails Fox, Kurama, inside Naruto. The Ōtsutsuki clans have been obsessed with these avatars of pure chakra and overall weapons of mass destruction, so with just a touch, Momoshiki could have gotten two soldiers for the price of one. Honestly speaking, a Tailed Beast owned by Momoshiki would truly be apocalyptic.
That said, even if he corrupts either Naruto or Kurama, they operate with such a synergy that co-opting one means the other won't be too far behind. Sadly, Boruto wasn't in his right mind while all this was occurring, so he couldn't have stopped this potential marking. Only time will tell, but if Momoshiki does indeed get control of Naruto someday, maybe Kurama might have to jump into Boruto. And based on how this manga's going, with all of its twists and turns, Momoshiki's endgame and the fate of the Konoha heroes will likely leave fans reeling.