Karui is a kunoichi of Kumogakure, and a member of Team Samui. The team was sent to Konoha by the Fourth Raikage to inform them that they would be taking care of Sasuke Uchiha and Akatsuki. She, along with the other two members of her team, are Killer Bee's students.

Karui seems to have a somewhat comedic-negative relationship with her teammate, Omoi. During their debut, they 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 implying that she is flat-chested in comparison to their teammate, Samui. However, like the rest of her team, she highly respects Killer Bee.

Karui is also quite outspoken and allows her emotions to let out, as she angrily yelled at Team Kakashi to allow the renegade Sasuke to run loose. She came to a violent point when she took out her rage on Naruto and beat him.

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, using slick, precise movements as they work well together. Karui has good strength, she punched Naruto hard enough to make him bleed instantly.

"Karui" means "light" or "non-serious" in Japanese, as a contrast to Omoi's name.