Karui

is a kunoichi of Kumogakure and a member of Team Samui. The team is sent to Konoha by the Raikage to inform them that they would be taking care of Sasuke Uchiha and Akatsuki. In her first appearance, she and Omoi argued over the possible reasons that they could have been called by the Raikage. She assumed that he wanted them to get him more protein shakes. However, the argument started with Omoi implicating to her about being flat chested in comparison to their teammate, Samui. She, along with the other two members of her team, are Kirābī's students.

Hunt for the Eight-Tails
In her first appearance, she and Omoi argued over the possible reasons that they could have been called by the Raikage. Omoi thought he was going to be scolded for putting mayonnaise on his potatoes; the argument started, however, with Omoi suggesting that Samui's back problems stem from her large breasts, something Karui doesn't need to worry about.

Summit of the Five Kage
Later, after Naruto's victory over Nagato, Karui and her team are seen traveling to Konoha, when Omoi worries that once they get there, a girl will fall for him and once he has to leave, she'll commit suicide out of loneliness. During that short argument with him, Karui throws a rock at him. While Omoi worries that she could have buried Konoha had she caused an avalanche, Karui angrily yells that he overreacts too much. After they arrive at Konoha, they are shocked to find a giant crater in its place (caused by Pain's Shinra Tensei shortly before his battle with Naruto). Omoi blames Karui for the crater being there, while Samui says they should ask someone for information on what happened.

Karui and Omoi overheard Naruto and Sakura talking about Sasuke, so they attacked Naruto, Sakura & Sai. Later they explain that Sasuke attacked and captured their Sensei and that he's an Akatsuki member. Karui then insulted Sasuke in front of Sakura causing her to cry, but was stopped by Sai pointing out that they should not pressurize and blame her.

Swordsmanship Specialist
In terms of fighting style, Karui relies mainly on swordplay, and thus would be considered a swordsmanship specialist. She and Omoi use attack combos together, with swords, with slick, precise movements, as their chemistry together is really good.

Trivia

 * "Karui" means "lightweight" in Japanese. It is the opposite of Omoi's name.