He is an Anbu from Konohagakure.
He has short shaggy brown hair and wears a white fox-like mask with two blue markings on either side of the face. He wears the standard attire of the Konoha Anbu.
As an Anbu, he is presumably a very powerful shinobi. He carries a sword hinting at skill in kenjutsu. He has demonstrated skill with shuriken, being able to effectively hit multiple targets without missing.
Yakumo Kurama Rescue Mission
He was ordered to protect Yakumo Kurama and the house she was staying as well as to keep watch over her unstable genjutsu powers. After she managed to sneak out and attack Konoha, he along with two medical-nin restrained her and brought her back to the household before Naruto Uzumaki could interfere. Later he and the two medical-nin became surround by unknown shinobi. After sending one of the medical-nin to get help, he confronted the intruders and seemingly defeated them all before realising he was trapped in a genjutsu. He was later rescued after the Kurama clan was defeated by Guy's squad.
During Pain's attack on Konoha, he, Yugao Uzuki, and two other Anbu protected Tsunade as she was using Katsuyu to tend to the villagers injury's. When Pain approached the group, he and the Anbu concentrated chakra to their feet to combat their opponent's ability. When Pain unleashed a large-scale attack, he was caught in the impact and separated from the rest of the group. It is unknown what happened to him after wards.
This Anbu shares the same mask design and hairstyle with a member from Team Ro and a Root member in Naruto: Shippūden episode 135.
He is the first anime-only character to make an appearance in a canon arc.