In the Naruto franchise, the titular ninja had quite a rivalry with Sasuke, eventually becoming sworn enemies. Naruto wanted to become the Hokage -- i.e. the leader of Konoha -- while Sasuke wanted to destroy it as he felt the village betrayed his Uchiha Clan.
But following the threat of Kaguya, both reconciled, and after having kids of their own, they're overseeing the new generation in Konoha to help protect the Five Village Ninja Alliance. As the Boruto franchise focuses on Naruto's son and Sasuke's daughter, Sarada, shaping the future, one character has been thrown into the mix who may be the most dangerous yet: Kawaki.
KAWAKI'S PAST & PERSONALITY
Following the Boruto movie, the anime introduced Kawaki in its opening shot. With Konoha seemingly destroyed, and Boruto as a young adult, it appears both are in a fight to the death, with Kawaki even teasing he killed Naruto himself. While the anime is still catching up, the manga has given us much more backstory into Kawaki, revealing he's more or less the new Sasuke.
He's always sulking and brooding, but his background is just as tragic. He was rescued by Naruto after the youth escaped the new terrorist organization known as Kara. Naruto senses he's on the verge of being weaponized, just like what Orochimaru tried to do with Sasuke, and wants to inspire him, along with Boruto, to be a true hero.
Kawaki, however, is bitter because his memory is broken, and all he knows is that he was a lab experiment put together by Kara's scientists. Just like Sasuke wanted to kill Itachi (his brother) for slaying his clan, Kawaki has nothing but resentment in him, which Naruto knows will consume and force him down a dark path. The manga shows Kawaki being protective of Boruto's sister, Himwari, though, which means he does appreciate a sense of family. However, with that snapshot of the future looming, it seems he'll give into hate.
Kawaki holds the Kama mark, which allows him to absorb all ninja techniques (whether they're fire, air, water or earth-based), and spit them back out. Naruto's shocked because he hasn't seen someone who can warp chakra like this since Kaguya, which makes the boy a weapon of mass destruction.
Thus, Naruto wants to teach Kawaki to follow the principles of chakra and inner-energy, as opposed to treating his abilities as if he's a loaded gun. In other words, Naruto wants Kawaki to feel less like a machine and more like a man who has control of these gifts. Seeing as Konoha isn't as scientifically advanced, we don't know what further powers Kawaki holds and how he'll evolve with this Kama mark, which seems like it harbors unlimited possibilities.
Kawaki's other big asset is his regenerative ability, making him nearly unbeatable in battle, and when coupled with how he can manipulate and mold his arms (think of Clayface from Batman), he already exceeds the potential shown by Boruto and his peers. But as Kara hunts their prized possession using the likes of Delta and Koji Kashin, it's obvious Kawaki is on the cusp of unlocking additional powers sooner rather than later.
We know right now Kawaki's destiny is set in stone as a villain in how he's dead-set on killing Boruto. He thinks this was always their fate, which draws strong parallels to how Sasuke turned on Naruto in the Shippuden era. But we know redemption is a big part of this franchise, so if Boruto can talk him out of it, they can become brothers-in-arms like the preceding generation.
Kawaki might even be closer to becoming the next Hokage as he has shown an affinity for Naruto's brand of leadership, while Boruto simply wants to be free and patrol the wilderness like Sasuke, instead of following in his father's footsteps. But as it stands, Kawaki is just too unpredictable, because we have no clue where his real allegiance lies or how he'll eventually give in to Kara's corruption.
That said, Kawaki definitely has all the makings of a hero. It just boils down to whether or not Boruto can help him channel his power and attitude, and if he truly does want to make amends on his own like Sasuke did. Kara is a big influence on Kawaki and we don't know his family history, so until clarity's gained on both fronts, he'll simply remain a wildcard that could either help save the world or break it completely.