He had one more technique he hadn't truly mastered: the Eight Gates.
The Eight Gates worked by stimulating the body's meridians to open its limiters, greatly amplifying chakra and physical strength and granting immense power.
But his body had no meridians, and the power of the first seven gates would do little for him anyway. If he wanted to use the Eight Gates, he would have to open the Gate of Death directly and enter the Eight Gates Released Formation for it to have any effect.
The Eight Gates Released Formation was extremely difficult to master. Even with complete instructions, he couldn't learn it in a short time. It would take time to analyze, and opening the Gate of Death was especially challenging.
The only way would be to study someone using the Eight Gates Released Formation. But Might Guy was the only person who could use it, and once he did, he would be left crippled.
Although his Yin-Yang Release had improved greatly, he still couldn't completely heal the aftereffects of the Eight Gates Released Formation.
So he put the matter aside for now. Might Guy was one of Konoha's hidden trump cards; he couldn't be used carelessly. Guy would have a vital role to play in the future—in short, he was a strategic weapon.
Besides, with his current abilities, he didn't need a technique like the Eight Gates. His overall strength was already at the Six Paths level, and he wasn't afraid of even Six Paths Madara as depicted in the anime.
That was just his own assessment, of course. He'd never actually fought a battle like that, so he couldn't know for sure.
The Otsutsuki Clan was an enemy he would have to face. They were the natural enemy of chakra: ninjutsu made of chakra had no