Board Thread:Theories and Speculation/@comment-26388300-20160325102110/@comment-28869806-20160415014939

UltimaDude wrote: Uchiahmasters wrote: it is still enough to keep him from getting rusty, and beside it's very uncharacteristic of Sasuke to stop training. Not really. How? There's no reason to keep training do you even realize why Sasuke went on that journey to begin with, it was to repent for his sins yes, but it was also so he could make sure that what happened with Kaguya would never happen again, that alone is good enough reason to keep training.

and he was also searching for information about Kaguya, such as why someone on her level would need an army, he suspected that it was so she could fight against a stronger opponent, so he knew that there was someone she feared, and had been preparing to have to fight him should the need arise, meaning Sasuke might have to team up with Naruto to fight this greater threat.