I think this unknown otsutsuki defeated shibai and forced him to leave his body. If shibai revives, I think this missing otsutsuki helps Boruto and kawaki to eliminate shibai. I think shibai is the main villain of the plot. I think shibai will revive through jura. Also, we do not know what is the true origin of the ten tails.
I always wonder if black zetsu in Naruto shippuden is actually kaguya's karma. Many secrets relating to karma are yet to be revealed.
I think Karma placed by otsutsuki may take life form if such karma is thrown into air, without implanting in a person like it happened with black zetsu's birth
