Heart & Key

Heart & Key is the ending of Kingdom Hearts χ Back Cover. Like Blank Points, Signs of What's Next, and Another Guardian of Light, this cutscene utilizes in-game graphics and voice acting. It ends with the phrase "Reconnect. Kingdom Hearts," and it does not tease a future addition to the Kingdom Hearts series. Instead, it serves as a true ending and acts as a prologue to Kingdom Hearts III.

Synopsis
Luxu stands alone in the Keyblade Graveyard, alongside the mysterious box and given to him by the Master of Masters. Luxu studies his new weapon for a moment, and he looks to the sky as he says, "May my heart be my guiding key."