WARNING: The following article contains major spoilers for Boruto: Naruto Next Generations #36, by Masashi Kishimoto, Mikio Ikemoto and Ukyo Kodachi, on sale now.
The Boruto manga took some time to start revealing more about the terrorist cell known as Kara, but in the last few issues, its threat has become abundantly apparent. Sasuke's figured out Jigen, the leader, is an alien with links to Kaguya's clan and the Ten Tails monster, while the Hokage himself already battled Delta, one of Jigen's generals.
However, the Kara member shrouded in secrecy the most has been Koji Kashin. The scout's regarded as one of the cell's best soldiers, although he has been operating with his own agenda. With Jigen losing patience and arriving at Naruto's home, though, it seems like Koji has had enough of Jigen's insubordination and he could become a very unlikely ally to Naruto.
Due to his long grey hair and reluctance to attack Konoha, some fans theorize that Jigen was actually Naruto's mentor and godfather, Jiraiya. The latter died in Naruto: Shippuden fighting the Akatsuki, but speculation has it he somehow returned to life as Koji. The fact he was able to pass through Konoha's chakra barrier meant he has to be a citizen and, since he can summon warrior frogs like Jiraiya and Naruto, all signs point to Koji being Jiraiya, Konoha's legendary Sannin.
Even when Delta fought Naruto, Koji just took mental notes. He had no interesting in engaging anyone, and when he sparred with Boruto in the past, it came off like he was just assessing the boy. Koji's position as friend or foe is called into question once more in the latest chapter when Jigen teleports in and accosts the newly-transformed Kawaki in Naruto's living room. However, as he does so, Koji's taken aback because his mission was to monitor and retrieve Kawaki since Jigen allegedly couldn't track the vessel.
Koji seems afraid when Jigen spots him from far away running surveillance. While Koji was keeping his cards close to chest and buying time to figure out Jigen's endgame, Jigen was actually testing Koji and dissecting his true intentions, which Delta questioned in the past. Koji quickly realizes he wasn't playing Jigen, but that he was being played by Jigen. When Koji teleports out, Jigen catches him in the act and gives him a deadly glance that makes consequences seem all but certain.
Koji's apparently failed this test of loyalty and knowing that Jigen will reward punishment with death, he might have to quickly drop his cloak and reveal his identity to Naruto. If he's Jiraiya, fans will want to know how he was revived and why he didn't play a role in the later wars against Kaguya and her clan.That still doesn't explain why he stayed in the shadows for so long. He could've been embedded deep cover the same way Itachi was with the Akatsuki, but if this is the case, the explanation better be worthwhile.
If he isn't Jiraiya, Koji will be on the top of Kara's hit list so it'll be in his best interests to partner with the Konoha military. He also has deep insight into Jigen's science lab and the running of Kara, so coupling this info on their setup along with Sasuke's recon work, the Hokage might actually be able to formulate a planl to take down Jigen and his sinister associates. If anything, Jigen's first act of war at Naruto's home reiterates the great Hokage's need for as much help as he can get. Sasuke, Boruto and the new generation of shinobi won't be enough, but maybe someone from inside the belly of the beast like Koji canl be the trump card Konoha desperately needs.