Dono means master.
Because he has respect for Kisame. He also calls Sasori "Master Sasori".
Kisame & Itachi Sasori & Deidara Deidara & Tobi Konan & Pein Kakuzu & Hidan Zetsu
They met when Pain sent Sasori, Kisame, and Itachi to find Deidara to recruit him for the Akatsuki. Once Deidara joined the Akatsuki, he and Sasori became partners.
There aren't any episodes with them together like talking, but there is one with Itachi, Kisame, and Sasori trying to talk Deidara into joining the akatsuki in Shippuden episode 124. And there is a few episodes in the beginning of Shippuden where they fight different people indirectly.
I would say Suigetsu... or maybe Deidara.
Somewhere in Naruto Shippuden Manga Chapter 358-360 I think..
Cuz he wants to.
Deidara's full life story is still a mystery. All that is proved is that he was a rogue ninja, and Akatsuki noticed him, so they sent Itachi, Kisame, and Sasori to bring him to Akatsuki. Deidara disagreed, so Itachi challenged him. Itachi won, and brought Deidara back to the Akatsuki. Ever since, Deidara was in Akatsuki. That was his past.
Deidara Hidan Kisame Hoshigaki Kakazu Konan Orochimaru(previously) Nagato Sasori Tobi Yahiko Zetsu
Sasori hidan tobi nagato kisame kohnan zetsu itachi deidara kakuzu orochimaru (former)
1. Tobi (Madara Uchiha) 2. Pain 3. Kisame 4. Deidara 5.Konan 6. Itachi 7. Zetsu 8. Kisame 9. Kakuzu 10. Hidan 11. Sasori
All of the akatuki members: Tobi Zetsu Itachi Sasori Deidara Pain Kisame Kakuzu Hidan Konan And Finaly!! Orochimaru!!