Naruto: Returning to Ancestry from the Warring States Period to Become an Otsutsuki

Jiang Dong unexpectedly transmigrates into the world of Naruto, becoming Shugo Senju. When he meets Hashirama, still sporting a bowl cut, and Tobirama, a cold, white-haired boy, he immediately realizes:

This is one hell of an era-even little children can die at any moment.

All he can do is train-for survival, for the chance to stay alive.

Fortunately, he has a cheat ability of his own: the power to devour bloodlines and awaken their ancestral origins. After one ancestral awakening after another, he becomes an Otsutsuki and rises to the pinnacle.

(The setting primarily follows the anime, since the author has only watched the anime and is merely familiar with the manga. As for power levels, readers keep equating the chakra-concentration mechanic with actual combat strength, completely ignoring his record of killing Kage. Then there are claims that money didn't exist in the Warring States Period and people only stole things; readers who skip around without reading the explanations; claims that all the Uchiha in the Warring States Period already knew about Susanoo before Madara awakened his Mangekyo Sharingan; claims that the peak-jonin rank only existed during the Konoha era; complaints about applying an Indra template to Hashirama; and complaints that the protagonist transmigrated into a Senju with poor ninja aptitude yet wanted revenge while he was still weak, while ignoring the care and support Tobirama and Hashirama gave him...)