Yuffie

Yuffie Kisaragi is a character from Final Fantasy VII who makes an appearance in all Kingdom Hearts games. She travels with Leon, whom she refers to by his real name, Squall - this usually causes annoyance on Squall's part. She sometimes refers to herself as the "Great Ninja Yuffie", wielding a large wind-blade shuriken as her weapon.

She is hyperactive but tires out easily due to her high energy and quick movement. She is hard-working and determined, set on repairing her home of Radiant Garden and aiding Sora in his campaign against the Heartless and other foes. She is teased frequently about her weight by the Gullwings despite not being overweight, and during the ending sequence she tries to hand an ice cream cone to Cid but is interrupted by the Gullwings.

Kingdom Hearts
''A female ninja who escaped to Traverse Town when her home world was taken by the Heartless. She stays strong and cheerful in any situation. She works with Leon and Aerith to unravel the secret of the "key".''

Kingdom Hearts: Chain of Memories
''A girl whose cheerful personality belies her painful memories. When she was still young, the Heartless robbed her of her home.''

Never one to sweat the small stuff, Yuffie seems unfazed by her fuddled memory.

Kingdom Hearts II
One member of the town's Restoration Committee, a spirited girl who actively does her part to keep tabs on the town.

''Yuffie met Sora when she was living away from her hometown. Thanks to his help last time, the Heartless were ousted and she got to come home - so she's very grateful to him.''

Kingdom Hearts
Sora's first meeting with Yuffie is in Traverse Town, where Sora accidentally mistakes her for Kairi while still partially asleep. Yuffie does not play a significant role in the story, but she, along with Leon, was the one who told Sora about the keyblade while inside the Traverse Town hotel. Rikku from Final Fantasy X was going to take Yuffie's place as Squall's assistant, but because there already was a main character named Riku, they removed her and substituted her with Yuffie.

In the fight cups at Olympus Coliseum, Yuffie is fought numerous times by herself and alongside Squall. She fights primarily by throwing small shuriken and swinging her larger one as a weapon, but she is also able to recover lost health if she is not interrupted.

Kingdom Hearts: Chain of Memories
Modeled after the real Yuffie based on Sora's memories. She doesn't remember Sora, but Sora's heart makes her remember, which she classes as strange yet convenient.

Kingdom Hearts II
Yuffie is featured more prominently in this game than the previous two. She is the first person to meet Sora as his party enters Hollow Bastion and leads them to Merlin's house. There, she introduces the familiar friends from Traverse Town and the Hollow Bastion Restoration Committee (the latter of which she is a member of).

She explains about the town's defense system to Sora, Donald and Goofy and, later on in the game, fights alongside Sora in the Ravine Trail during the invasion of Hollow Bastion. Once she and Sora clear the area of enemies, she leaves to assist Squall and the others.

As in Kingdom Hearts, she is available to fight in the tournament cups in the Underworld at Olympus Coliseum.

Battle
In battle, Yuffie uses slashing and throwing attacks similar to those of her Final Fantasy Counterpart. She also uses "Greased Lightning" to jump into the air and throw a shuriken. She can even heal herself by using her ability "Clear Tranquil". When enraged she will use "Doom of The Living" where she throws a gigantic, magically infused shuriken at her opponent. In Kingdom Hearts 2, Yuffie can teleport leaving smoke and blowing leaves behind. She uses her shuriken exculsively as a close range weapon this time around and has a powerful attack where she charges it up with magic and lets it fly around her.

Trivia

 * In a cutscene in Kingdom Hearts, Sora mistakenly takes Yuffie for Kairi when he was awaken by her after fighting Squall, who told he to call him Leon.
 * Yuffie's role was originally filled by Rikku, but due to the fact that there was already a major character named Riku in the series, they decided to replace her with Yuffie. Traces of Rikku's intended attire remain on Yuffie during Kingdom Hearts and Chain of Memories. By Kingdom Hearts II, Yuffie wore the clothing she had on Final Fantasy VII: Advent Children.
 * In the Japanese version, Yuffie was voiced by popular actress Yumi Kakazu, who also voiced Yuffie in other incarnations Final Fantasy VII.
 * In the English version of Kingdom Hearts, Yuffie was voiced by Christy Carlson Romano, who voiced Yuffie in Advent Children.
 * In the English version of Kingdom Hearts II, Yuffie's voice actress was replaced by Mae Whitman, who also voiced her in Dirge of Cerberus.