Roxas is Sora's Nobody and a former member of Organization XIII, born when Sora took his own heart. Although Sora's heart was soon restored, Roxas continued to endure and exist, oblivious of Sora's existence for most of his life. Prior to the events of Kingdom Hearts II Roxas was Rank XIII within the Organization, and bore the title Key of Destiny (めぐりあう鍵, Meguriau Kagi?, lit. Serendipitous Key) because of his ability to wield the Keyblade. He wields light, and uses it to direct rays that strike opponents with great power. He commands the Samurai Nobodies.

Roxas was also the mysterious hooded figure in "Another side, Another story..." as well as in Deep Dive. During the prologue of Kingdom Hearts II, the player controls Roxas until Sora is awakened. In Kingdom Hearts 358/2 Days, Roxas is the main character. This game focuses on the time period between Roxas's birth and his departure from the Organization, eventually leading to his capture at the hands of Riku and DiZ.