Two Powers…!! (二つの力…!!, Futatsu no Chikara…!!) is chapter 645 of the Naruto manga.
After the conversation between father and son, Naruto dons his Tailed Beast Mode shroud as he plans to attack Obito with renewed vigour. Before so, Tobirama reminds the latter that only senjutsu-based attacks could damage the Ten-Tails' jinchūriki, causing Naruto to panic since he had forgotten already. Inside Naruto's mind, Yang-Kurama tells Naruto that since both of them are on friendly terms, Naruto can use Sage Mode whilst using its power similar to the time the young shinobi conversed with Nagato. On the other hand, Yin-Kurama also tells Minato that he can also under-go a full Tailed Beast Mode transformation to provide powerful support for his son. Following the advice of the beast, Naruto goes full Tailed Beast Mode in sync with his Sage Mode while Minato unleashes his Tailed Beast Mode as well. Minato, with Naruto's help, prepares a large-scale, senjutsu-infused Rasengan, and with Tobirama's Flying Thunder God Technique, quickly slams it unto Obito, who uses chakra arms and a fluid barrier to repel the attack. Noting the barrier's durability, Naruto and Minato pool their strengths together to form a senjutsu-infused Tailed Beast Ball to destroy the opponent's defences. Meanwhile, Sasuke, along with the surviving shinobi, watch the battle as the Uchiha ponders just how far Naruto had come. Obito then undergoes his own tailed beast transformation, planning to continue the Eye of the Moon Plan, shocking Madara, who was still battling Hashirama.