The Dive to the Heart is a location which appears in Kingdom Hearts, Kingdom Hearts II, Kingdom Hearts coded, Kingdom Hearts Birth by Sleep and their respective remakes. It is a world within a dream, and its nature as the dreamer's heart is reinforced by the background music, the gameplay tutorial, and the strange way of speaking used by those within it. However, the events which occur within it have a real effect on the waking world, and in two instances they are actually observed by outside forces. In terms of gameplay, the purpose of the Dive to the Heart is to serve as a tutorial level, where the player will learn the controls of the game, choose how their character will grow, and fight their first boss.
To reinforce the dreamlike setting of the Dive to the Heart, Sora, Roxas, and Ventus each reach it by falling into an ocean. However, instead of drowning they find that they can breathe, and land upon an ocean floor which erupts into doves, revealing the Dive to the Heart. In Roxas's case, this first Dive to the Heart is merely a memory of Sora's, and he enters his true dive three days later. The Dive to the Heart is composed of several enormous, illuminated stained-glass pillars known as "Stations", rising from unseen depths. Each Station has a unique shade, depicts a specific set of characters, and has its own specific part in the tutorial. In the first game, there is an additional area of the Dive to the Heart based on the Destiny Islands. The background music, "Dive Into the Heart (Destati)", initially begins quietly and hard to hear, but grows in intensity as Sora or Roxas approach the final pillar, where they fight a manifestation of the darkness within them. At the end of their battle with the creature, the Dive to the Heart is consumed by the darkness emanating from it, dragging Sora or Roxas with it, but they either wake up or are rescued.