OD did a translation of the chapter where sasuke talks about what he's been doing all these years.
Sasuke said
We already know that the white zetsu army is pre-shinobi since Kaguya's era was before ninjutsu was even thing. So why is he telling us this? I think it's because the only thing he found out about kaguya's history is this new threat so he's just repeating things we already know to make it seem like he had a good reason to leave his family for 12 years. :bdpf:
Sasuke said
And then…First of all, I discovered that the army of Shiro Zetsu was something that was produced a long time ago, and before Shinobi were born