Board Thread:Theories and Speculation/@comment-34700383-20180709211419/@comment-33156027-20180710140354

You're talking about that "darkness" as a real thing, like some kind of power or entity. That "darkness" is just in the mind, and I think calling it as the darkness is just in metaphorical way, same as Uchiha clan curse of hatred (this is not a real curse). Of course chakra can changed it aura by influence of the state of mind, sensor type shinobi can read someones emotions by his chakra, but this is only influence. Everything is in the mind, so Sasuke just turns back to the light side of the force and there is some hatred and "darkness" in him, but who doesn't have some? I think Sasuke is clear now and propably never return to his previous path of vengeance and hatred, because he has no reson to do so, especially when he has a child and wife now and there are peace and union in shinobi world. He finished his redemption and now he is traveling because this is his mission, to find things connected with Kaguya and Otsutsuki clan who are still a threats to the shinobi world.