Is Deidara dead?

Deidara killed himself to beat Sasuke, but the young Uchiha shielded himself by summoning a giant snake to hide behind.

Why does Tobi act childish?

A: Obito Uchiha was taking on the false persona of Tobi to artfully control the Akatsuki and execute his “master-plan.” He was actually the akatsukis leader and posing as Madara Uchiha. He chose Tobi’s child-like behavior because it deflected suspicion and was entertaining in its irony.

Who is Deidara shipped with?

Deidara x Sasori Deidara and Sasori are partners in the Akatsuki, but there are plenty of fans who see them as partners in more ways than one. The two do argue a lot, but Deidara appears to hold Sasori in high esteem, both as a fighter and as an artist.