WARNING: The following contains major spoilers for Boruto: Naruto Next Generations #45, by Masashi Kishimoto, Mikio Ikemoto and Ukyo Kodachi, available in English from Viz Media.
Boruto #45 brings a lot of hidden truths to light when Kara's science chief, Amado, finally makes his defection to Konoha official. It's not the smoothest of transitions, though, as he did hold Shikamaru's kid hostage, but eventually Naruto and his council listen to the man who helped create Kawaki and other soldiers for Jigen.
In the process, as Amado spills secrets to hopefully give Konoha the edge in the war to come, we discover Jigen's deadliest legion isn't even the Kara terrorist cell. That's because he has a farm of Ten Tails monsters he can call upon if the battle gets too tough.
The Ten Tails is the monster Kaguya used to wreak havoc on Earth in the Naruto franchise. It's a staple of the Ōtsutsuki clan and when the raging behemoth was split by Kaguya's sons, Hagomoro and Hamura, it became the nine Tailed Beasts that roamed the planet. However, there's a bit more in this issue, as throughout history they've been scattered across various planets as seedlings. While maturing, the Ten Tails grow into God Trees, which suck the chakra out of all the planet's inhabitants and create a fruit for the Ōtsutsuki aliens to feast on.
This is how the clan thrived, moving from planet to planet to sate its hunger. However, in Kaguya's case, she found a tree here already and merged with it to reform a Ten Tails so she could get unique and original chakra back from her sons. They defeated her, though, and sealed her in a husk, which became the moon, not realizing she left her essence behind in the Zetsu project that kickstarted the war in the Naruto series. So, this beast is apocalyptic and contains the power of all Tailed Beasts. It's no wonder Naruto, Sasuke and all the united ninja villages struggled to put it down. It's why, when Sasuke saw Jigen had one chained down in a hidden space-time region, he immediately had a sinking feeling. But according to Amado, there's more of where that came from.
Apparently, each group of Ōtsutsuki travellers wanders the cosmos with a Ten Tails. It's not known whose was it Kaguya met or if she seeded it out and came to it as a mature tree when she arrived, but Amado says this Ten Tails Jigen has is all new. It seems the person who's using Jigen as a vessel, Isshiki, dropped it to secretly grow in this dimension. Amado reveals these monsters are the Ōtsutsuki's watchdogs, prepping the planets and sucking the life out of everyone like parasites. Admittedly, it's not known if the chakra flows to the tree naturally when people die or if it latches onto them via its roots and drains them like the Shippuden era stories. To hear Jigen has access to more, and whether they're full-grown or kids, it's chilling as they're enough to enslave planets. And it Jigen wants he could simply use a portal, head home and bring back more.
These creatures come off like xenomorphs, warped hunters the Ōtsutsuki clan use to conquer. Notably, they're a massive step up from modified soldiers Kawaki and company represent. They're pretty powerful on a human level, but one Ten Tails alone could conquer Earth. Just imagine if Jigen upgraded his arsenal with more by transporting them over as backup. Naruto and Sasuke don't want to alarm anyone but you can tell after the last Ten Tails nearly wiped out the entire alliance, they can't handle the fact there's a whole farm of these creatures waiting somewhere and possibly eyeing Earth again. Jigen has one right now, but if he decides to turn that into many, then consider the game over.
