Kurotsuchi

黒ツチ

Kurotsuchi is a female shinobi who along with Akatsuchi escorts the Third Tsuchikage, who is her grandfather. She refers to Deidara as Deidara-nii (nii-san = big brother), either as family or a sign of respect.
Some time after the Fourth Shinobi World War her grandfather retired and she became the Fourth Tsuchikage