Rō

is an Anbu of Konohagakure.

Appearance
Rō has thick eyebrows, a strong jaw and stubborn, one-lidded eyes. Due to him having a very old-fashioned speech pattern, coupled with his round, boulder-like appearance, he seems more like a samurai than a shinobi. While on duty, he wears a monkey mask.

Abilities
Rō has the ability to make a target's chakra appear to be smaller or larger than it actually is, or even non-existant. However, he notes that this technique is only useful in deceit, and doesn't actually change the amount of chakra his target possesses.

Shikamaru Hiden: A Cloud Drifting in Silent Darkness
When Shikamaru was tasked with infiltrating the Land of Silence with the dual purpose of finding missing shinobi, including Sai, and assassinating country head Gengo, the Sixth Hokage, Kakashi Hatake, assigned Soku and Rō to aid him. After showing off his abilities, Rō and the rest of the group departed at dawn at the hidden back entrance to Konoha. After arriving in the Curtain Village and assessing the situation, Rō and the rest of his squad are quickly captured by Gengo's Enlightened Ones. During captivity, he is tortured by them.

When he and the rest are brought before Gengo, he nearly succeeds in placing him and the rest in his mind-altering genjutsu until the timely arrival of Temari and her Suna and Konoha reinforcements breaks Gengo's hold on them. Rō engages the brainwashed shinobi by restraining them despite the injuries he received from torture. During Shikamaru and Gengo's fight in the darkness, the Anbu helps out his leader by disguising his leader's chakra so that the missing-nin could not sense his movements. With the mission accomplished, Rō prepares to escort Shikamaru back to Konoha with the rest of the Konoha personnel.

Trivia

 * means "haziness".