WARNING: The following contains spoilers for the Boruto: Naruto Next Generations anime, Episode 100: "The Predestined Path."
Much to the delight of fans, the Boruto anime is giving a lot more agency to the titular young hero than the manga. We're seeing Naruto's son being coddled less and embarking on more missions with heaps of responsibility. However, this exposure is bringing him into the crosshairs of unsavory individuals, the likes of which his dad tried to shield him from within the confines of Konoha.
One of these new faces storming into the young shinobi's life is an old one from Naruto's past, and this encounter brings nothing but danger and pain. This comes in the form of Naruto: Shippuden's very own 'Incredible Hulk' -- Jugo.
When Naruto first met Jugo, he quickly became a nemesis allied with Sasuke's Taka, also known as "Team Hawk." Jugo became Sasuke's bodyguard after they left Orochimaru, pledging fealty to the fallen Konoha ninja because he literally helped enhance Sasuke's form. Jugo's cells could store and transform chakra unlike any other, so Orochimaru used him in experiments to help refine Sasuke's makeup and weaponize him. As for Jugo, the downside was that he was basically turned into a Jekyll-and-Hyde character who morphed into a giant beast when he lost control.
Going from a mild-mannered ninja to such a behemoth led to fans dubbing him Naruto's very own Hulk. And like Marvel's Bruce Banner, Jugo was indeed a walking, talking weapon of mass destruction, although when Sasuke eventually turned over a new leaf, so did Jugo. His loyalty shifted to Naruto's alliance, although his bond of brotherhood with Sasuke remained unbreakable. And who can blame either Naruto or Sasuke for wanting Jugo alongside them, as he held the power to level cities? Even more scary was that he was still developing thanks to Orochimaru's experiments, leaving us clueless as to what his true form could be. Until now.
In the latest episode, Boruto and his squadron come upon a mysterious infection at a nearby river village, where birds and the water itself are dispersing the virus. It turns out that Cursed Seals -- which basically turn people into super-powered zombies -- are spreading, and Boruto finds Jugo trying to stymie the epidemic. The way he does this, though, is unique; due to his own marks, Jugo can absorb the corrupted ones and cure the victims. But it appears he's feeling the after-effects of this, and is going mad.
Jugo is struggling with his own inner-demons, trying to quell the beast within, which he tries to suppress via special injections. This is barely taming him, however, and now that he's absorbing the marks of others, he finds himself transforming into something much worse than ever before. Eventually, Jugo goes into berserker mode, and as he attacks Boruto's camp, he's gone from someone who can grow huge, dragon like arms and wings, to some sort of indestructible super-gargoyle with huge trunks growing out his back. He's stronger, fiercer and more bloodthirsty than ever, which endangers, not just this community on the fringes, but Konoha and all other outskirt neighbors.
Boruto's naive to all this. He simply can't believe his timid friend could turn into such a devastating monster. But diehard fans aren't surprised as they know Jugo's genetics were considered even stronger than Naruto by Orochimaru and could one day go haywire to create a monster unlike any Naruto, Boruto or anyone else has seen before.
Sadly, that time has come. Jugo's gone off the rails, and unless Boruto finds a permanent cure, he's poised to go on a rampage that may require intervention from the Hokage himself, or Sasuke (who hasn't been seen for a while due to his roaming missions). This time, as much as they've avoided it in the past, Naruto and the other seniors who come to the fore might have to put Jugo down for good.