"The Ten-Tails' Jinchūriki: Obito" (十尾の人柱力・オビト, Jūbi no Jinchūriki: Obito) is chapter 638 of the original Naruto manga.
The shinobi watch on in confusion as the Ten-Tails vanishes from the battlefield. As the shinobi sought answers, Hiashi watched on with his Byakugan, and Sakura asked Hinata, what she had seen. It is revealed that Obito, had in fact initiated a sealing technique, which allowed him to absorb the Ten-Tails into himself, making him the beast's new jinchūriki. Emerging in his new form, Naruto goes on to confirm that Obito was able to resist Madara's control and had instead been using a different technique than the one to revive him. Meanwhile, Killer B confirms with Gyūki that the Ten-Tails had not reached its final form but had instead been sealed within Obito. Hashirama then attempts to restrain Obito, but Obito's new power proves too much for the technique which had been restraining the beast itself prior. In response, Obito generates four chakra arms, and then proceeds to rip apart the barrier erected by the four Hokage. Upon seeing this, Hashirama warns the other shinobi of Obito's power while Minato pleads for Obito to stop which is responded to by Obito sounding out his own name with some confusion. As the three other Hokage relocate to where Obito is, Hashirama openly declares that Obito is stronger than he, which both Hiruzen and Tobirama affirm. As Madara prepares his own "trump card" hoping that Obito did not notice him before then. While the Hokage discussed the situation, Obito takes the First and Second by surprise, ripping through their bodies.
To commemorate the 45th anniversary of Weekly Shōnen Jump a special full-color edition of Naruto chapter 638 was published as an exclusive for the premium digital issue of Weekly Shōnen Jump No. 33 and the official English release of the chapter.