Kingdom Hearts 358/2 Days is an action role-playing video game developed by h.a.n.d. and Square Enix in collaboration with Disney Interactive Studios for the Nintendo DS. It is the fifth installment in the Kingdom Hearts series, and takes place near the end of the first game in parallel to Kingdom Hearts: Chain of Memories, leading directly into the events of Kingdom Hearts II. The game was released worldwide in 2009. The story is told from the perspective of Roxas, and follows his daily life within Organization XIII and his relationship with fellow Organization member Axel; it also introduces a fourteenth member, Xion, who befriends them.

Kingdom Hearts is a 2002 action role-playing video game developed by Square for the PlayStation 2 video game console. It is the first game in the Kingdom Hearts series and is the result of a collaboration between Square and The Walt Disney Company. An expanded re-release of the game featuring new and additional content, Kingdom Hearts Final Mix, was released exclusively in Japan in December 2002. The Final Mix version of the game was later remastered in high definition and released globally as a part of the Kingdom Hearts HD 1.5 Remix collection for the PlayStation 3. The game was later ported and released as part of the bundled Kingdom Hearts HD 1.5 + 2.5 Remix collection for PlayStation 4 in March 2017, Xbox One in February 2020, Windows in March 2021, and Nintendo Switch in February 2022.