"A new technique? You want to use a technique you never used before and which has a high chance of failing versus such a strong foe? You think I would allow that?" - Yamato took his mask off to lock straight into Naruto's eyes.
Taking the mask off during an Anbu mission was unheard of, but he was responsible for Naruto - not only because Tsunade entrusted him with that, but because Kakashi was his senpai, so he needed to make sure that Naruto meant what he said. And he felt that hiding behind a mask, he wouldn't be able to get a clear answer from Naruto.
Naruto saw Yamato's face for the first time, and after the initial surprise that he took the mask off, he returned to a serious expression, and with clear eyes, he said: "I can do it. Please trust me. I'm a Konoha-shinobi too - not just a Jinchuriki which needs to be protected nonstop."
Yamato smiled.
At first, he didn't understand why Tsunade wanted Naruto to participate in this mission - until now he seemed more like baggage than a reliable teammate.
If he didn't need to protect Naruto, he could have helped the rest of the Anbu which would have been way better in his opinion.
But Naruto showed now his spirit and determination, befitting of a Konoha shinobi who inherited the Will of Fire.
This was also noticed by Sakura: 'Naruto...when did you grow up so much? Compared to you, I'm still relying on others like always...even if Sasuke is so close...'
"Alright, I'll permit it. I don't know what your plan is, so I'll support you with my Jutsus. However, if I see that you don't stand a chance, I'll pull you out of the fight immediately, understood?" - Yamato
Unlawfully taken from Royal Road, this story should be reported if seen on Amazon.
Naruto nodded and got ready.
There was no better time to enter than now: the Anbu desperately managed to get closer to Kakuzu and when they finally got an opening for the Anbu who could use lighting release, the lighting infused Kunai he threw hit Kakuzu, and when he activated his hand signs, lightning went through Kakuzu's whole body and burned his innards - or at least that's what was supposed to happen.
When he was hit by the Kunai, Kakuzu just detached one of his Lighting masks (he had two since the first mask was destroyed by Jiraiya back then, but then he took the hearts of the Anbu with Lightining nature) and the body of the Lightning mask monster was electrified instead.
Since it had lighting affinity, it didn't do much damage to it's heart, so it was ineffective.
While the Anbu were surprised by what happened, his threads stroke the Anbu and tore through his chest.
"Tsk, again lighting nature? I seem to get unlucky a bit here...whatever, it's not like I need all four elements o defeat you small fries." - Kakuzu looked around and thought it would be better to finish his fight quickly, so he detached all four mask monster from his body...and he started blasting.
His masks used all their offensive techniques at the same time and soon the battlefield was full of huge firestorms and lighting spears flying around.
"Damn it...we lost our sole chance...what do we do? I don't think we stand a chance..." - Anbu A
"We can only hope that he either runs out of chakra first or that we manage to drag it out enough that Lord Jiraiya can reinforce us..." - Anbu B
After his barrage of attacks, when the smoke settled, Kakuzu either expected to see Anbu corpses or that they fled, but instead it was Naruto standing there with the hand signs of the Shadowclone Jutsu.
"So you finally decided to stop hiding yourself behind your comrades? Good, this makes it easier for me..." - Kakuzu wasn't that talkative compared to other villains, so he stopped it at that and recalled one of the Lighting monsters into his body and started to move his threads towards Naruto's body.
He needed to capture him alive, so he didn't bombard him as he did with the Anbu.
Naruto was that, but he didn't dodge because the next moment a woodwall appeared and blocked the thread-arm.
In the meantime, four shadow clones appeared, and with them, he rushed towards Kakuzu.
This looked like a typical Naruto attack, but he was in fact already planning ahead so that his new technique would definitely land!