After they all finished their food, Minato and Kushina followed Kannin into the woods. When he thought he reached a point far enough away from prying eyes, he turned to Minato and asked,
"Is anyone watching us?"
"Not that I can sense."
"Good. No one else can know about this, okay?"
Kushina was no longer annoyed, but incredibly curious. This grey-haired kid was finally going to prove he was an Uzumaki. Well, at least he claimed he would. Kannin summoned for the first time outside his home the Adamantine Chains he had spent the last year or so developing. Kushina was shocked, though still skeptical.
"It might look like our Adamantine Chains, but they're probably just fakes, a genjutsu or something."
Kannin understood her skepticism, she was part of a near dead clan, she couldn't accept any Tom, Dick, and Harry who claimed to be one, especially one that didn't even have their red hair, but at this point it was a bit ridiculous. He let one of the chains touch Kushina, and to her shock, she felt her chakra being drained through it. While Kushina didn't want to admit it, she could no longer deny Kannin as an Uzumaki.
"How is your hair grey, then?" She asked.
"My father." Kannin said, "He was a half Uzumaki living in Uzushiogakure where he met my mom. They left around the same time you did, but my father died before I was born, and my mother was a civilian, so she doesn't know any of our techniques. I have been denied my heritage for a long time; the only way I learned the Adamantine Chains was because I discovered the method among the ruins of Uzushiogakure myself a year ago."
"I think I can understand that, Kannin. I'm sorry I doubted you for so long, it's just hard to imagine anyone without red hair as an Uzumaki."
Kannin chuckled at that comment, given how her own son would have Minato's yellow hair, but he said "I understand, Kushina. To be honest, I don't know if I would've believed me in your position."
"So what do you want to learn?"
"Fuinjutsu. I think we all know war is coming quickly, and I want to be prepared for it as best I can."
"That'll be difficult, but doable. Minato was wanting to learn too, so maybe we could do tutoring sessions or something."
"You're going to teach Minato secret Uzumaki fuinjutsu?" He said with a joking intonation.
Kushina blushed a little and didn't respond.
They decided that she would teach him every Monday and Thursday, which was fine by him given his use of shadow clones would likely increase his progress.
-
For the next year Kannin stayed in training. His progress under Kushina was slow at first, but as he got the hang of the basics and underlying logic of fuinjutsu, his proficiency increased substantially. He also became quite close with Kushina. Once she had gotten to trust him, they bonded over their similar backgrounds; Kannin, of course, couldn't fully understand what it was like being the Kyuubi's jinchuriki, but they both felt the pains of being some of the last Uzumakis in the world. Her personality also mellowed out after a while, and once you got to know her, she was quite a fun person to be around.
He had learned the Four Symbols Seal and Eight Trigrams Seal, as well as some smaller ones which were mainly improved versions of regular sealing jutsu. Minato also regularly sat in on their sessions, and it was at those times were Kannin got to see first hand Minato's genius. He intuited the forms and functions of the seals at almost twice the pace Kannin did, and even theorized how to apply it to his other jutsu and make them more efficient, especially his Flying Thunder God.
Speaking of, it was over the course of that year that Kannin saw Minato's skill with Flying Thunder God explode. He was innovating new ways to use it and in forms even Tobirama probably couldn't imagine. Thinking on it, he knew Nidaime Hokage would be proud that someone like Minato came along to perfect his jutsu. And Minato would need it dearly for the war.
The past year also saw Kannin gain an affinity with Lightning Release through his training. In fact, every member of Team 4 managed to get proficient with another nature release: Warai learned earth release and Tetsu learned wind release. All in all, Team 4 was one of the strongest shinobi teams in Konoha, maybe second only to Minato's.
But with all the progress he and his friends had made, the political climate had taken a turn for the worse. Negotiations with Sunagakure had completely fallen apart, and it looked like Konoha would have to stand alone against the might of Kumogakure and Iwagakure combined--perhaps even Sunagakure if things really got bad. Konoha had formed alliances with many of the smaller villages, but Hiruzen was still quite concerned about how things would play out once war did break out. Most of all, he needed high level shinobi talent.
The Land of Fire is blessed with a higher population than the other lands due to its arable land, so it did have the population to deal with another nation or two in war, but they didn't seem to have the talent pound for pound. Each village had at least one jinchuriki, one Kage, and usually many more kage-level talents. Thankfully Konoha had the Sannin, but they never seemed to be in the village anymore.
Hiruzen was dreading what the future had in store, especially with Danzo's dabbling. Kannin was also dreading the future. He didn't know if his mother could take another war, especially one that would have him on the front line. He was confident in his power, and especially in the power of his team, but he nonetheless was not excited about the war.