In Naruto Shippuden, Tobi's seemingly childish and goofy personality was a carefully constructed facade. Beneath the mask was ...

He later stopped acting goofy to introduce himself as “Madara,” but Madara’s physical appearance ... first revealed his Kamui space-time jutsu in the exact same arc in which Tobi debuted.

Obito may have made his first appearance as himself during the Fourth Great Ninja War, yet he has remained in the backdrop since the beginning of Shippuden as a mysterious character named Tobi.