1(Naruto)

An Au where Indra wasn't manipulated by Zetsu but controlled by him as Indra during his trip fell in love with a young man(the ancestor of the Hatakes) and thought about informing his father that he didn't wish to be his her as he wanted to stay with his lover but just as they had their first(and only) child, Zetsu got his hands on Indra and made things happen as they did in canon(including having Indra marry someone else and become the ancestor of the Uchihas).

But unlike canon, Indra did not reincarnate often like Asura but his spirit stayed beside his descendants(the Uchihas since they were the ones Zetsu was interested in) and kept them as safe as he could from Zetsu's manipulation/control.

Unfortunately he wasn't able to stop it all but when Madara left Konoha, he was able to convince Madara to kill himself before Zetsu got his hands completely on him but Madara did leave a letter behind for Hashirama and the Uchihas that was passed down by every generation till Danzo got his hands on them and burned it and blamed it disappearance on some poor soul.

Indra wasn't happy with what he was seeing Danzo do especially as he was seeing the descendants of his love and brother be whipped so he decided to act and suck a bit of his bijuu siblings chakra and become material so he could deal with Danzo and save the Hatakes and Uzumakis(and with that also Obito and some others) before he went back to simply being a spirit leaving the bijuus worried about what had suddenly taken a bit of their chakra and how they did it as it couldn't have been their jailers.

That still left Zetsu able to try and control others but Indra found a way to do it after one of his descendants(Sasuke), a descendant of his brother(Naruto), a descendant of his love(Kakashi) and a descendant of his could have been sister-in-law(Sakura) were able to see him so he got their help and joining Sasuke and Naruto's chakra they were able to contact his father and get his help.

Anything else if up to the writer.