Kingdom Hearts

Kingdom Hearts is the game series' namesake. Kingdom Hearts generally refers to a heart shaped moon that is said to be the heart of all Worlds. The moon color changes depending on how it is summoned. In Kingdom Hearts II the moon is shown with an off-white tint, due to being comprised of the hearts freed from Heartless, whereas in Birth by Sleep the moon is a blue tint due to having been summoned by Master Xehanort in expectation of unlocking it with the χ-Blade, ending up with it being comprised of the hearts of Worlds. The doors that allow access to Kingdom Hearts has only appeared in Kingdom Hearts and Kingdom Hearts II, the appearances of them varying slightly. The doors are extremely large, shown to require multiple people to close them and requiring multiple people to open them in the case of the Kingdom Hearts II incarnation. The doors are also decorated with a multi-colored stain glass window at the top of the door.