Windhole (風穴, Kazaana) is chapter 629 of the Naruto manga.
The Tenpenchii technique used by the Ten-Tails culminates disastrously, still causing powerful twisters and lightning strikes, leading a Susanoo-clad Madara to assume that most of the Allied Shinobi Forces had been wiped out by the attack. However, as the battlefield clears, the shinobi are all revealed to be alive and well, having been protected by their respective shrouds. Before the seemingly confused Ten-Tails, Naruto stands bleeding and exhausted, but still smiling confidently. Looking on, the Ten-Tails sees the images of the tailed beasts (sans Gyūki and Shukaku) behind Naruto, and ultimately a silhouette with the Rinnegan staring back at him. Shocked, the beast undergoes another transformation, as the shrouds vanish from around the shinobi, and Naruto falls to one knee, very fatigued. Madara — who notes that the fight had started to bore him, and he had already found something else to preoccupy his time — turns in time to see the Alliance rally around Naruto, providing a defence for him while Sakura begins to heal him. Elsewhere, as Kakashi and Obito enter Kamui's dimension, Kakashi is the first to regain his footing and attack, but stops just short of driving his Lightning Cutter through Obito's heart. Trying to speak sense to his former friend, even though Obito decries his actions and tries to play on his conscience, Kakashi notes that he had long since realised that Obito was trying to overlap his old self with Naruto. Obito, however, notes that he was doing it for the exact opposite reason and then declares that he did not wage a war in the world just for Rin. With this, Obito phases through Kakashi's Lightning Cutter, then recreates the scene where Kakashi had killed Rin in the same manner. He then reveals that he knew the truth of how Kirigakure had made Rin into Isobu's jinchūriki with the sole intention of destroying Konohagakure, and how Rin had impaled herself on Kakashi's Lightning Cutter in order to protect the village. He then states that it was the system of the villages, and the shinobi that he intended to destroy because no good came of it. With this, Obito announces that he is incapable of feeling pain, and shows Kakashi that there was no heart in his chest, just a windhole which was caused by the hell of this world.