|This is the article on the chapter. For the actual technique, head to Night Guy.|
"Night Guy…!!" (夜ガイ…!!, Yagai…!!) is chapter 672 of the original Naruto manga.
As Guy prepares his strongest technique, Madara notes that this is his opponent's last attack based on his chakra levels. While Naruto and Sasuke awaken and prepare to head back onto the battlefield, Lee and Gaara watched the gruesome battle between Guy and Madara wage on. Meanwhile, Kakashi remembers the first time he and his father met Might Guy and Might Duy at the Academy.
While Guy burns his body and radiates a massive aura, similar to a dragon, the Ten-Tails' jinchūriki shows his excitement about this, but quickly becomes shocked by Guy's speed and ability to distort space when he tries to counter-attack. Guy attacks with a powerful kick, which entirely decimates the left side of Madara's upper body, almost killing him, and creates a massive hole in the Ten-Tails' tree form. After his last attack, Guy distresses when his heart's pressure point is about to fade, and his body starts to deteriorate. While recovering from the attack, Madara launches one of his black orbs, intent on being the one to kill Guy; however, Naruto suddenly appears and kicks it back to him. Laying his hand on Guy, the latter's life force begins to return to his body slowly. As Madara notes that the young man had changed, Naruto notes as well, that he indeed felt like he could change the world with his new power.