Eagle-Masked Anbu Member

He is an anbu member that appears through-out the series.

Three-Tails' Appearance
In the anime, he and his partner were part of a Anbu team that was tasked to watch over the Three-Tails. After arriving and relieving Kakashi's group of watch, the group stationed themselves at the lake to write reports to send back to Konoha. While on watch, he and his partner were attacked by Deidara and quickly defeated.