Kitane

was once a member of the Twelve Guardian Ninja. He appears to have once been friends with Asuma Sarutobi before his death.

Background
While he was still alive, he was part of the Twelve Guardian Ninja. Ten years before the start of the series, when six of the members tried a coup d'etat, he alongside Asuma Sarutobi, Chiriku, Nauma, Tōu, and Seito fought against them, only to be killed by Kazuma when Kitane and the three other lightning users tried to use Limelight on Kazuma.

Abilities
He along with Nauma, Tōu, and Seito were known as the greatest lightning-chakra masters of their time. Like Asuma, his battle style revolved around combining superb taijutsu skill with his elemental affinity through a unique weapon. He used a three-parted metal staff to fight with, that is also able to conduct his lightning based attacks.

Nature Transformation
Kitane could send lightning through the ground to attack by striking his staff into the ground. When separating his staff into three pieces he can use his Lightning Release: Thunder Binding to form a barrier around a target. When in one of the four cardinal directions, he along with Nauma, Tōu, and Seito could use a technique called Limelight to destroy everything within that area to ash.

Twelve Guardian Ninja Arc
During the beginning of the filler arc is his, Nauma's, Tōu's, and Seito's corpses are stolen by grave robbers, and later revived using lightning. After being revived they were all approached by Asuma who had figured out the scheme of the robbers. There he tries without luck to stop the three who seem to have become mindless puppets, while Kitane, the only one of them who still seems to think clearly, attacks Asuma, saying that he cannot go against his summoner's orders.

He was later "killed" again by Asuma before he got to the Limelight spot. When Kazuma's plan failed he decided to release the summoned Nauma, Tōu and Seito. Of course, Kitane would never want to hurt Asuma, but since he was revived by Kazuma and was under his control, he did not have a choice.