Axel

Axel (アクセル, Akuseru), the "Flurry of Dancing Flames" (おどる火の風, Odoru Hi no Kaze), is a Nobody introduced in Kingdom Hearts: Chain of Memories. His original self is named Lea (リア, Ria), and was originally friends with Isa before he became Saïx. Much like his original self, Axel wishes to achieve his own ideal of immortality by having everyone he comes in contact with remember him, saying the phrase "Got it memorized?" on multiple occasions. Entrusted to deal with Organization traitors, Axel controls the Assassin Nobodies, and fights with a pair of "chakrams" called "Eternal Flames" (エターナルフレイム, Etānaru Fureimu) and fire manipulation. Axel is assigned to Castle Oblivion during the events of Kingdom Hearts: Chain of Memories, pretending to join with Larxene and Marluxia in their plan to seize control of the Organization. He kills Vexen to gain their trust, but finds himself confronting Sora while Marluxia uses Namine as a shield. Nomura designed Axel based on a similar concept as Reno from Final Fantasy VII; Nomura wanted to see what it would be like to have a similar character in a different role and world. The character is voiced by Keiji Fujiwara in the Japanese release of the games, while Quinton Flynn provided the voice for English releases.
During Kingdom Hearts II, Axel is ordered by the Organization to capture their lost member Roxas who was also his friend. Roxas refuses to return with him and ends defeating him before merging with Sora. Axel later begins acting on his own and kidnaps Kairi, but Saïx takes her under Xemnas's orders. Axel later finds Sora in a pathway to the World That Never Was and chooses to fight the Nobodies with him. Outnumbered, Axel performs a suicide attack to save Sora, and using the last of his strength to open the entrance to the World That Never Was. When asked what he was trying to do, Axel admits he wanted to see Roxas.
While acting as Roxas's mentor in the first half of 358/2 Days, he befriends the new Nobody as well as the other new member, Xion, eventually learning that Xion is an imperfect replica of Sora created by Xemnas. Upon learning the truth, Axel reluctantly hides it from Roxas while being forced in hunting down Xion when she attempts to leave the Organization. After Roxas abandons the Organization, Axel recaptures Xion, refusing to let her sacrifice herself.
Axel makes a cameo in the secret ending of Kingdom Hearts Birth By Sleep on Twilight Town's clock tower along with Roxas and Xion. The scene is explored in Kingdom Hearts coded, revealing that Axel is connected to Sora's heart. In Kingdom Hearts 3D: Dream Drop Distance, Axel's death is shown to have revived Lea, who spends the game searching for Braig and Isa. In doing so, he becomes an ally of Sora and his companions, rescuing Sora from the newly formed Organization. By the end of the game, Lea reveals himself to have become a Keyblade Wielder