Kage (Anbu)

is a member of Konohagakure's ANBU.

Background
Kage is part of "ANBU Team 1" and was the first on the list of ANBU members that was given to Orochimaru by Sai. He reliably accomplishes his missions and he is known for his ability to approach his target under the cover of darkness, moving like a shadow. "Kage" is likely a codename.