Here it is, Mr. Zetsu, I found it. Maybe now I can become a member of the Akatsuki - Tobi One explanation for the rings disappearance could be attributed to the Akatsuki members defeat over time.

Back when the Naruto manga was still releasing chapters, there was a running mystery regarding a mask-wearing member of Akatsuki, Tobi, and his identity. The idea of him being Obito Uchiha ...