Zō

He is a Captain in Konohagakure's Anbu force.

Appearance
Like all other Anbu captains, he is dressed in a white cloak and black trousers with bandages tied around his right leg and black sandals. He also has spiky black hair and his mask has a cat motif with three red whisker-like markings

Abilities
Though it is unknown if he was the same person in all his appearances, he has shown a wide variety of abilities inclusive of the manipulation of fire and lightning nature transformations. For example, he can cause four rock pillars to spring from the ground and shoot lightning at the enemy to pin them down. After a large amount of mud is put on pillars by his partner, he can use a more powerful version to trap the opponent in the form of a oven like structure. From there the opponent can be cooked by firing the oven also hardening the mud and trapping the opponent further if he survives. He is also adapt at genjutsu, being able to cast an illusion that causes the target to recall memories they would otherwise not remember. In case he is on the verge of death or being captured, he can use a technique to completely destroy his body with no traces of it left behind whatsoever.

Invasion of Konoha Arc
The Anbu captain and seven other Anbu members were stationed in the Chūnin Exam arena during the final rounds of the Chūnin Exams. When Orochimaru launched the invasion of Konoha, the Anbu captain and his team rushed to help the Third Hokage. However, before they could reach him, the Sound Four put up a barrier that kept them from helping. He and his men were forced to watch the battle between the Third Hokage and Orochimaru. In the end, the Third Hokage died due to using the Dead Demon Consuming Seal and Orochimaru stabbing him with the Sword of Kusanagi: Longsword of the Sky. When Orochimaru retreated, the Anbu captain and his men tried to prevent them from escaping, but Kidōmaru prevented them from following with his webs. At the Third Hokage's funeral, the captain cursed his inability to help the Hokage, saying "In the end, all we could do was watch".

Trap Master Arc
In the anime, a similar-looking Anbu captain and his team interrogated Naruto about Gennō by using the Time Reversal Technique.

Three-Tails Arc
In the anime, a similar-looking Anbu captain was badly wounded by Kabuto on a mission trying to find the location of one of Orochimaru's hideouts. He sent a messenger bird back to Konoha with information about his mission before destroying his body.

Invasion of Pain Arc
He was later seen during the invasion of Pain and stayed by Tsunade's side in order to protect her, as she healed the villagers, and later accompanied Ino when she went to aid her father and Ibiki Morino. This Anbu captain defeated one of Pain's summons using Lightning Release: Four Pillar Bind with the aid of two other unnamed Anbu captains.

Trivia

 * This Anbu captain has been given the name Otomatsu by fans and the closed captioning. He has also been called Raidō, possibly because he was confused with Raidō Namiashi.
 * The other Anbu were once seen wearing black cloaks, while their leader wore a white cloak giving a distinction between their leader and them.
 * There have been several appearances of an unnamed Anbu captain from Konohagakure, wearing white robes and a cat-like mask. It is unknown if any of these appearance are the same person. In the anime, there are at least two of them, as the second to appear died shortly afterwards.