Darui

is a Jōnin-level ninja of Kumogakure, who currently functions as a bodyguard and escort to Ē, the Fourth Raikage at the Kage summit, along with his fellow jōnin Shī.

Personality
In his first appearance, Darui is portrayed as easy-going and mellow; when compared to Ē's over-the-top exit through a window, (destroying a wall along with it), he tells Shī that he'll just use the door. Whilst having a more laid-back demeanor compared to his leader, Darui isn't lazy, leaping to Ē's defense when the bodyguards of the other Kage overreact to the Raikage's reactions.

Appearance
Darui has a dark skin tone, a slightly bulbous nose, a lazy look in his eyes and white hair in a shaggy hair style. He also appears to be quite tall in stature. Darui has so far only been seen in the sleeveless uniform and one-strap-over-one-shoulder Flak Jacket of a Kumogakure Jōnin. Darui also has the characters for and  tattooed on his right and left shoulders respectively, presumably denoting his chakra's elemental nature affinities; Water Release and Lightning Release.

As a sword-user, Darui wields a large, cleaver-like blade, which is seen carried on his back during the Kage summit, although he doesn't seem to carry it around at his home village.

Swordsmanship
When Ē smashed the table and the bodyguards moved to protect their respective Kage, Darui showed a long and fairly broad sword that seems a little particular from others swords as it folds in two to be sheathed and unfolds when in use. He has shown quite some skills in kenjutsu, as he was able to clash with Suigetsu Hōzuki's (albeit broken) Decapitating Carving Knife, and can charge his broad sword with electricity that can stay charged even when he isn't making contact with it.

Elemental Techniques
Darui has also shown to be proficient with Water Release and Lightning Release techniques, possibly being able to use them both simultaneously. Darui is shown using what is presumably a Kekkei Genkai known as Storm Release, which possibly combines both Lightning and Water chakra to create beams of light that can be guided like missiles and cause powerful explosions.

Like Killer Bee, Darui is also proficient with the use of "Chakra Flow" with ballistic weapons; he has been seen using a Lightning-empowered shuriken to slice through a metal blade in-order to save Killer Bee from Kisame Hoshigaki's attempt to cut off Killer Bee's legs.

Five Kage Summit arc
He and Shī were chosen to escort Ē to the Five Kage Summit in the Land of Iron. When Ē jumped through a window, he tells Shī that he'd rather use the door. During the Kage meeting, he quickly jumped to protect Ē after he smashed the table, because the bodyguards of the other Kage entered into defensive position. After the other bodyguards returned to their respective place, Darui and Shī did the same.

When White Zetsu appears during the Five Kage Summit, Darui, along with Shī, guards Ē and follow him to the meeting with Sasuke Uchiha. Suigetsu charged at Shī only to be stopped by Darui and they started battling. Darui and Suigetsu continue their sword fight while Ē deals with Jūgo and Sasuke. Darui then incapacitates Suigetsu by stabbing a blade into his chest and instilling it with Lighting Release. He then goes to assist Shī who had been knocked unconscious by Sasuke's genjutsu. He watched as Ē seemingly sacrificed his arm and prepares to deal a final blow to Sasuke.

Sasuke counters, and Ē is saved from further injury by Gaara. As Ē is being healed by Shī, Darui decides to help Gaara, Temari and Kankurō in defeating Sasuke. As they all attack together, Sasuke once again counters with a new form of Susanoo. After Sasuke uses Susanoo to collapse the ceiling onto his enemies, Darui is protected by a sand shield conjured by Gaara. Afterward, he follows Ē to chase down Sasuke.

Upon returning to the meeting hall, Darui finds that Madara Uchiha has rescued Sasuke and Karin and teleported them out of danger. Madara then proceeds to tell them about his Moon's Eye Plan to rule the world by unlocking the Ten-Tailed Beast and casting an Infinite Tsukuyomi. When Madara asks them to hand over the Eight-Tailed Giant Ox and Nine-Tailed Demon Fox, and notes that Killer Bee has escaped, Darui notes that it was something that Killer Bee would do.

Darui, along with Shī and the Ē are on route back to the Land of Lightning to make arrangements to the Shinobi Alliance. Later, in chapter #473, a timely-thrown lightning-empowered Shuriken from Darui saves a weakened Killer Bee from Kisame Hoshigaki's attempt to slice off Killer Bee's legs. Ē's entourage were drawn to the area by the sight of Kisame's massive deluge from a mile away, as well as Shī sensing all of the heightened activity from the Eight-Tailed Giant Ox's chakra. Darui comments upon how foolish and careless it was of Kisame to have absorbed the chakra of both Killer Bee and the Eight-Tail's and then use it all so recklessly out in the open.

After Killer Bee and Ē decapitate Kisame with their collaborative Double Lariat technique, Darui, along with Shī, watch from the sidelines as the newly-reunited brothers start to bicker over Killer Bee's running away from Kumogakure.

Trivia

 * Darui is Japanese for "sluggish," "dull," referring to his lazy, languid way of speaking.