Universe of Kingdom Hearts

In the Universe of Kingdom Hearts there are many worlds that fall into certain realms. All of these realms are on their own plane of existence. These planes are parallel to each other except for Realm of Nothingness.

Plane
A Plane or Plane of Existence is a flat surface with infinite width and length. There are only two planes in Kingdom Hearts. These planes have been dubbed with the names of the Realm of Light and the Realm of Darkness. The worlds that are visited in Kingdom Hearts belong to one of the two planes with the exception of Castle Oblivion, Twilight Town, Yen Sid's Tower and The World That Never Was which exist between these two planes in the Realm of In Between.

The Realm of Light contains all the 'normal' worlds such as Destiny Islands, Deep Jungle, and Halloween Town. The Realm of Darkness is only known to contain Kingdom Hearts. It can be conjectured that the Realm of Nothingness takes place outside of the planes and not in the between area. These planes or realms should not be confused with worlds, however traveling from plane to plane or to the places in between the planes can be done via Gummi Ship, Corridor of Darkness, and even stairs just like worlds. Traveling between planes can also be done via Doors, such as the Door To Light and the Door To Darkness. The planes as well as the areas outside are a part of the Sea of Outer Space.

Stairs were only mentioned once by Tetsuya Nomura's in the Director's Secret Report XIII. Tetsuya Nomura's stated that to fully imagine the Kingdom Hearts universe correctly "you can imagine two planes with stairs ranging between the worlds (on the planes)".

Realm of Light
The Realm of Light (光の世界) is a Plane of Existence made up mostly of light and makes up almost half of the Kingdom Hearts universe, similar to the Realm of Darkness. Like the Realm of Darkness, the Realm of Light has a Keyblade, notably the Kingdom Key, which chose Sora as its wielder. Most of the game's worlds are found here, save for those in the Realm of In Between, like Twilight Town, Castle Oblivion, and The World That Never Was. It can be presumed that most of the Worlds accessible by the Gummi Ship are either within the Realm of Light, or are related to it, like Twilight Town.

In Kingdom Hearts II, one notable citation has been made by Sora regarding the Realm of Light during the scene of Sora and Riku at the "end of the road" after defeating Xemnas: ''The other side... The realm of light is safe now. Kairi, the King and the others are there.''

The door leading to the Realm of Light is called the Door to Light. It's opposite counterpart is the Door To Darkness. It was the door Sora and Riku went through while they were stuck in the Realm of Darkness. It is not sure what caused the door to appear, one reason could be, as Riku pointed out at the end of the game was the light within Sora's Heart which was brought out by Kairi's Letter.

Realm of Darkness
The Realm of Darkness (闇の世界) is a Plane of Existence made up of Darkness in people in every world. As with the Realm of Light, this realm has a Keyblade which chose King Mickey as its wielder. Kingdom Hearts is found here. This is also the home of all the Heartless, as this is where the most powerful ones can be found. Sora fought Xehanort's Heartless in Kingdom Hearts.

Sora, Donald, Goofy visit the Realm of Darkness after being saved from Saïx by Maleficent in Hollow Bastion, where they encounter a man in a black cloak, later revealed to be Riku. Riku leaves a box with a picture of Hayner, Pence, Olette, and Roxas and a bar of sea-salt ice cream. In this same realm, the Keyblade reacts to the ice-cream and Sora opens a pathway. This is the first time that Sora, Donald, and Goofy are able to make their way to the Realm of Darkness in Kingdom Hearts II.

Corridor of Darkness
Corridors of Darkness are unpredictable pathways that interlink the worlds of the Kingdom Hearts universe. The Heartless use these extensively to reach other worlds, as do members of Organization XIII, their subordinate Nobodies, and many other characters. These pathways are formed out of Darkness, so it is unsafe for a normal person to travel them, because the constant use of these corridors would corrupt one's heart. However, the Heartless and the Nobodies don't have to worry about this, since the Heartless already have corrupted hearts, and the Nobodies do not have hearts to corrupt. However, one upside to this is that it provides a faster means of travel than the Gummi Ships.

Other characters who have used these corridors include Riku, Naminé, DiZ and even Pluto. Of these, only Riku, Naminé and DiZ have been responsible for summoning the portals, and only those lacking hearts to corrupt (Nobodies), and those who are darkness (Heartless) aren't affected, with two noted exceptions; According to Nomura in the Director's Secret Report XIII, Riku and Mickey aren't affected by darkness at all, due to some "secret similarities". Ironically, in the first Kingdom Hearts, after the faceoff in Neverland, Riku's heart was significantly weakened as he carelessly used a Corridor of Darkness to return to Hollow Bastion. Nomura goes further to state that DiZ and the Beast can successfully use the Corridors of Darkness, and perhaps open them, due to their particularly strong feelings or hatred. Furthermore, despite Sora having used the Corridors of Darkness several times before, he has not used them frequently enough to allow the Darkness to stain his heart, and the influential power of Darkness depends on the strength of a person's heart.

Anyone who has traveled in darkness for too long would show a few physical traits: their skin darkens and their eyes turn amber. This is especially true for Xehanort, whose Heartless and Nobody both have tan skin and amber eyes. In the case of Ansem the Wise, it is not so severe: he only has amber eyes.

Maleficent is also believed to travel the Corridors. Though she does not show the physical changes. This could be due to her trying to command the Darkness, instead of becoming one with it. It is also know that Pete travels the Corridors as well. He is known to be protected by the Darkness by Maleficent's magic.

In Kingdom Hearts Re:Chain of Memories, whilst DiZ gives out black cloaks to King Mickey and Riku, he says the cloaks protect the wearer from the darkness.

Dark Meridian
The Dark Meridian (referred to by Tetsuya Nomura as the Dark Coastline) is a mysterious place in Kingdom Hearts. It is first seen in "Another Side, Another Story" (Deep Dive) video. In the first cutscene of Kingdom Hearts II, Roxas on a dark, moonlit beach, where Xemnas appears. He talks to Roxas, telling him how much he looks like Sora.

It reappears in the end of Kingdom Hearts II. After defeating Xemnas, Riku and Sora end up on the Dark Meridian. Suddenly, after Sora reads a letter from Kairi, a door appears leading them to Destiny Islands. In Kingdom Hearts 358/2 Days, Roxas converses with Xemnas at the Dark Meridian.

According to Another Report, Nomura states that the Dark Meridian is "the tip of a world", i.e. the boundary between Darkness and In Between. Sora and Riku were on the coast of the side of In Between, and were looking over the sea in the Realm of Darkness. Having said thus, the Door to Light which appeared in the ending scene is reminiscent of a quote which recurs in the Kingdom Hearts series, albeit in different words: "Deep in the Darkness, there is Light".

Realm of In Between
The Realm of In Between (or the Realm of Twilight) is the third Plane of Existence in the Kingdom Hearts series, and lies between the Realm of Light and Realm of Darkness.

Thus far the only known Worlds to exist in this plane are: Traverse Town, Castle Oblivion, Twilight Town and The World that Never Was. Each world tied closer to the Realm of Light or the Realm of Darkness, with the exception of Twilight Town, which exists exactly in the middle. Yen Sid's Tower also exists in this Realm.

Realm of Nothingness
The Realm of Nothingness is the fourth Plane of Existence. Nothing exists here and if one stays in there for too long, they will cease to exist. The only way to survive here is to remember your past.

Sora and Riku briefly entered the Realm of Nothingness during their final battle with Xemnas (i.e. in his final form).

After being banished from Hollow Bastion by Xehanort, and his apprentices, Ansem the Wise wandered into the Realm of Nothingness and became DiZ. DiZ only managed to stay alive and prevent himself from going insane by continuing to think and write.

Worlds
A World (ワールド) is a location that appears in the Kingdom Hearts series. Serving as the "levels" for the games, Sora and other characters are charged with visiting and protecting them through the course of the series. By defending the worlds from the Heartless, Nobodies, or other enemies, Sora keeps the Darkness from spreading and the worlds from being manipulated or destroyed.

Each world that appears in the Kingdom Hearts series has its own distinct look, and for the most part hold true to the movies and cartoons they are based off of. Often the plot of the game in that world will be based on its original source. Almost all worlds can be visited in the course of the game and are part of the playthrough; there are exceptions, though, since some places can be seen in cinematics but not actually accessed by Sora's party.

It should be noted in this context, that "world" is not as we know now, synonymous with "planet".

World characteristics
There are over twenty worlds that have appeared in the Kingdom Hearts series so far. Most of them are based on Disney's animated features and contain locations and characters from or inspired by the films. As a result, worlds are greatly varied in appearance, style, and nature, as their sources range from the oldest cartoons created by Disney to more current movies in the Disney canon. The oldest source is the 1928 cartoon "Steamboat Willie", used as a basis for Timeless River, while the most recent inspiration for a world from Disney's animated features is 1999's Tarzan, the source for Deep Jungle. In Kingdom Hearts II, two live-action films, Pirates of the Caribbean: The Curse of the Black Pearl and Tron served as the foundation for the worlds Port Royal and Space Paranoids.

In addition to the Disney-based worlds, eight worlds are exclusives that were created by game developers Square-Enix just for the Kingdom Hearts series. They are not part of the Disney film canon, nor Square-Enix's games canon, but do tend to be populated with Square-Enix characters, especially from the Final Fantasy series, as well as the occasional Disney character or original characters created just for Kingdom Hearts.

Some worlds have names that don't seem to accurately reflect what is found there. A famous example is Neverland in Kingdom Hearts; Sora and company get to go through Captain Hook's ship and fly around the Clock Tower, but never actually reach the island Neverland where Peter Pan and Tinker Bell live. To further confuse things, some worlds in Kingdom Hearts II contain what could almost be considered sublevels or second worlds within them, such as the Underworld at Olympus Coliseum or Christmas Town in Halloween Town.

Kingdom Hearts
In certain worlds, a character from that area will be available to fight, and can replace Donald or Goofy in the party. Kingdom Hearts had six such worlds with party members.


 * Deep Jungle's party member is Tarzan.
 * Agrabah's party member is Aladdin.
 * Halloween Town's party member is Jack Skellington.
 * Atlantica's party member is Ariel.
 * Neverland's party member is Peter Pan.
 * Hollow Bastion's party member is Beast.

Kingdom Hearts II
Kingdom Hearts II increased the number of worlds with party characters to nine, putting a party member in almost every Disney-based world. Three characters from Kingdom Hearts returned for battle: Aladdin, Jack Skellington, and Beast, although Beast was moved from Hollow Bastion to his own world. Ariel reappeared in Atlantica, but no longer as a party character, Peter Pan became a Summon, and Simba became a party member. Also the game added two party members with the same name as another; Jack Skellington and Jack Sparrow. This is rectified for gameplay that Sora refers to Jack Sparrow as Captain. To make the world-based party members more useful, special attacks were developed for each character that Sora could call on in the heat of battle. Kingdom Hearts II also included the first Final Fantasy party character, Auron, and allowed Sora to fight alongside his best friend, Riku.


 * The Land of Dragons's party member is Mulan.
 * Beast's Castle's party member is Beast.
 * Olympus Coliseum's party member is Auron.
 * Port Royal's party member is Jack Sparrow.
 * Halloween Town's party member is Jack Skellington.
 * Agrabah's party member is Aladdin.
 * Pride Lands' party member is Simba.
 * Space Paranoids' party member is Tron.
 * The World That Never Was' party member is Riku.

Kingdom Hearts Birth by Sleep
According to scans, Kingdom Hearts Birth by Sleep will continue to use party members residing in specific worlds. All that is known is that Experiment 626 will be the party member for the new world Deep Space.

Star
Stars are massive, luminous balls of plasma that are held together by their own gravity.

In the Kingdom Hearts games, each star is the fragment of one specific world. Should a star stop shining, that would mean that particular world has disappeared from existence, most likely from destruction from the Heartless.

In Kingdom Hearts, many stars disappeared. In Mickey's letter to Donald (before Destiny Islands is attacked by the Heartless), Mickey mentions the fact that the stars have been disappearing, one by one, and so he went to find out why. When Donald and Goofy first arrived at Traverse Town, they discovered a star corresponding Destiny Islands fade out of existence. They were restored after Sora and his friends stopped Ansem's plan to plunge the world into darkness.

Travel
Travel between the worlds is normally impossible. The worlds are all protected by dimensional barriers that prevent outsiders from entering for the most part. However, these barriers can be broken, resulting in a meteor shower in that world.

In Kingdom Hearts and Kingdom Hearts II, Sora, Donald, and Goofy use the Gummi Ship to travel between worlds on the World Map, an event that serves as a mini-game between areas. Some worlds require certain special Gummi Blocks to access; for example, a special Navigation Gummi must be installed by Cid to unlock a second set of worlds in Kingdom Hearts. Once they reach them, the party can enter and then depart each world through its Save Points.

Three worlds can only be accessed by entering through other worlds and do not directly require use of a Gummi Ship:
 * 100 Acre Wood via Pooh's book in Traverse Town (Kingdom Hearts) and Hollow Bastion (Kingdom Hearts II).
 * Timeless River via the Hall of the Cornerstone at Disney Castle.
 * Space Paranoids via Ansem's computer in Hollow Bastion.

It should be noted that in Kingdom Hearts: Chain of Memories, there are no Gummi Ships; the worlds Sora visits are recreations from his memories from the first game brought to life on each floor of Castle Oblivion.

There are three known ways to travel through the worlds:
 * Piloting a Gummi Ship; as Gummi Ships are composed of fragments of shattered barriers, they are capable of passing through them.
 * Utilizing the Corridors of Darkness; this is a faster means of travel than the Gummi Ships, but those who use them are at great risk of being destroyed by the darkness.
 * Teleportation; Merlin was able to teleport himself, Sora, Donald, and Goofy from Hollow Bastion to Disney Castle.

History
According to the story told by Kairi's grandmother in the Hollow Bastion's Library, long ago there was one single world, that was constantly bathed in the warmth of Light. When people began to fight over the Light within their world, Darkness appeared in their hearts, and the world was consumed. However, fragments of light remained within the hearts of children. From this light, children were able to rebuild the lost world. But darkness still existed, that's why the worlds are separate from each other, divided, waiting for the true light to return. (It should be noted that this story is considered to be a fairy-tale, and should not be considered an accurate account of history).

Prior to Kingdom Hearts, the worlds were surrounded by barriers, to prevent outside interference, making it impossible for different worlds to have contact. The arrival of the Heartless caused the barriers between the worlds to crumble and disappear, and some worlds were even consumed by the Heartless. Gummi Blocks are actually pieces of these broken barriers. The metaphysics of this prior to Kingdom Hearts is unknown, but will probably be revealed in Kingdom Hearts Birth by Sleep.

It should be noted that: as the Keyblade master, Sora was originally told by Donald not to meddle in the affairs of other worlds, as doing so would negatively affect the natural order of the universe; however, he quickly realized that he had to interfere in order to protect the worlds and their inhabitants.