Kingdom Hearts is a Japanese RPG video game series that presents a marriage between Square Enix and Disney Interactive Studios. Boasting an in-depth plot akin to those of various Final Fantasy titles, Kingdom Hearts follows Sora and his fellow Keyblade Wielders through worlds both original and those featured in various Disney cinematic titles such as Beauty in the Beast, Hercules, The Little Mermaid, Alice in Wonderland, Pirates of the Carribian, Tron, and more.
The series begins with Sora, the protagonist, as a happy-go-lucky resident of the tranquil Destiny Islands. He and his friends Riku and Kairi dream of escaping their solitary lives and experiencing foreign worlds. Before they can cast off, the Heartless, shadowy creatures who hunger for the hearts of people and worlds alike, plunge their island into darkness. Sora manages to escape to another world and there discovers that he can use the Keyblade, a powerful weapon capable of vanquishing Heartless. He is soon after recruited by Donald and Goofy, King Mickey's right hands, in the effort to fight the Darkness that threatens to overtake the entire Realm of Light. To save the cosmos, restore his world, and reunite with his friends, Sora embarks on a journey that's taking a really long time to conclude.
The series spans 8 games so far, with 3 collections of the series containing the previous games but remaked in HD (i.e KH I.5, II.5, and II.8), and the current arc will conclude with a 9th arriving (hopefully) sometime around next year. These games are, in order of the plot's chronology: chi, Birth by Sleep, Kingdom Hearts, 358/2 Days, Chain of Memories, Kingdom Hearts II, coded, Dream Drop Distance, and the upcoming Kingdom Hearts III.
Heart: One of the three main components of one’s being, and a force synonymous with the soul. What hearts are made of is currently unknown (And attempts to create them have been unsuccessful), but it is known that a heart is primarily formed from both light and darkness, with the exception of the Seven Princesses of Heart (Seven maidens whose hearts are completely devoid of darkness) or beings with their light/darkness forcefully separated (Such as Ventus and Vanitas). Hearts are also responsible for one feeling emotion and, when one holds strong bonds with others, allow the being to be able to feel the emotions of others. Hearts separated from their bodies also possess additional capabilities, such as possessing others, traveling through time (As long as there is a version of themselves where they travel), and even surviving the destruction of their worlds. Those with exceptionally strong hearts are able to wield a Keyblade.
Mind: The second of the components that make up one’s being. The mind is what gives an individual life, and determines whether they are alive or dead, the force that wills the body to live and drives it to survive. Those of exceptionally strong will are able to survive with only their mind, lacking their heart or body, as showcased with the Lingering Will.
Body: The final part of a being’s existence. Bodies give both the heart and mind a vessel, for without them, it is an empty husk.
Memory: Functioning similar to memories in real life, memory in Kingdom Hearts make up a strong part of the heart’s existence, and possess actual reality, leading to significant side effects if a person’s memories are altered (Even going as far as rewriting reality itself). And while memories may be concealed or forgotten, they never truly “fade”, and the heart will recognize things the mind may not (A sort of "déjà vu" feeling), if that is the case. This is even inclusive of abstract ideas, such as writing, as seen in Kingdom Hearts coded, where even after Naminé erased the pages of Jiminy’s Journal, their memories remained intact.
Heartless: A creature formed when a heart falls to darkness. Heartless are completely lacking in emotion and intelligence, only having instinct to collect hearts. Their appearance wildly varies depending on the individual that fell. There exist two different types of Heartless, Purebloods (Which are designed as being virtually pure black) and Emblem (Which have the Heartless logo located somewhere on their bodies). As mentioned before, Heartless are generally mindless beasts who only desire to collect hearts, however, there exist three who are exempt from this (Ansem, Seeker of Darkness, Scar and Sora’s Heartless, the former two even able to maintain their original form), in addition to the Black Costume Heartless maintaining the ability to speak, but are still driven by the desire present in all Heartless.
Nobody: After a being becomes a Heartless, their body and mind are left to become Nobodies. Nobodies are generally white in appearance, and are essentially empty husks, only existing to be commanded. When the original being has strong enough will, they shall maintain their original form as a Nobody (As shown with the members of Organization XIII). When a strong-willed Nobody is slain, they leave behind a semblance of their original being (Essentially a type of spirit) in the form of an Absent Silhouette. If a person's Heartless and Nobody are destroyed, their original being is restored.
Unversed: Essentially avatars of a person's own negative emotions, Unversed are chaotic beings with drastically varying appearance. All Unversed originate from Vanitas, with the exception of two, the Symphony Master and the Cursed Coach, both of whom were created by Cinderella's stepmother and stepsisters (Lady Tremaine, Drizella and Anastasia).
Dream Eaters: Only existing in the Realm of Sleep, where worlds restored from darkness lie in slumber, there exist two different classifications of Dream Eaters, Spirits (Who eat nightmares and replace them with good dreams) and Nightmares (Who eat good dreams and replace them with nightmares).
Kingdom Hearts: The heart of all hearts, and the source of ultimate power and unlimited wisdom. Kingdom Hearts is the primordial source of all light in the Kingdom Hearts universe, and the origin of the hearts of both worlds and men. As a result of the ancient war over Kingdom Hearts known as the "Keyblade War", Kingdom Hearts was swallowed in the Realm of Darkness, never to be seen again. While there have existed false versions of Kingdom Hearts (Such as the heart of all men gathered by the Organization XIII, or the heart of all worlds sealed behind the Door to Darkness), they are merely shadows of Kingdom Hearts' true glory, which has remained undiscovered for the entire series.
χ-Blade: The counterpart to Kingdom Hearts and the item all Keyblades are modeled after. The χ-Blade acts as the only way to summon the door to Kingdom Hearts, and presumably the way to unlock it as well. At the end of the Keyblade War, the χ-Blade was shattered into 20 pieces, seven of light, and thirteen of darkness. These pieces would eventually "manifest" as the Seven Guardians of Light and the Thirteen Seekers of Darkness, whose fatal clash would recreate the χ-Blade and summon the true Kingdom Hearts.
Keyblade: A weapon originally forged in the image of the χ-Blade for the Keyblade War, the Keyblade has remained a prominent weapon used by most major characters in the series. Only those chosen by the Keyblade are able to wield it, and those who cannot will simply have the weapon disappear right from their hands. Keyblade Wielders are shown to have various different abilities relating to their Keyblades, including the ability to open or close any lock or door, channeling magic with enough ability to surpass most mages, remove hearts from one's body (Including their own, but this only applies to Keyblade Masters), summon and dismiss the Keyblade whenever they desire (Making it impossible to properly disarm a Keyblade Wielder) and transforming it into various different kinds of weapons for more varied offensive purposes (Such as close-quarters-combat, ranged combat or enhanced mobility). While normally a Keyblade Wielder can only wield one Keyblade, those harboring another heart are capable of wielding two (As seen with Sora and Roxas, the former of whom can even wield three through the aid of telekinesis).
Power of this Verse
Kingdom Hearts is a very powerful verse, containing several or so Massively FTL+ and at least Large Star level characters, which includes not only the series own original characters (ex. Sora, Riku, Aqua, Xehanort, Xemnas, Ansem, etc.), but also some from Disney (ex. King Mickey, Maleficent, etc.) and Final Fantasy (ex. Cloud, Sephiroth, etc.). Not entirely surprising given the series's cosmological setting, as well as its development by Square Enix, whose Final Fantasy series is notoriously formidable.
Also notable is the series's abundance of hax, which include gravity manipulation, time manipulation, spatial manipulation, mind manipulation, transfiguration, etc. These abilities are so common that even fodder Heartless, Nobodies, Unversed, and Dream Eaters have regular access to many of them. Moreover, many of the main cast are shown as capable of resisting most of these hax, whether via the Keyblade or otherwise.
With the upcoming games of KH3 and possible future games after it (given that Disney and Square Enix themselves have yet to call an end to the series), it is very likely that the series will gain even more feats, hax and abilities, and possibly even a bigger power boost.
Given that most of the Disney characters (such as those from Tarzan, The Lion King, Peter Pan, The Hunchback of Notre Dame, Pirates of the Caribbean, or The Nightmare Before Christmas) were strictly displayed at power levels close to those within their original movies when in the home "worlds", it is assumed that travellers between them, such as Sora, are automatically scaled in relation to the story that they are transported to, in order not to overwhelm and break it. In addition, it would also lead to them being very inconsistent with what they've shown in their respective movies as just because they fought alongside or against Sora and the others doesn't mean that they are automatically scaled to 4-B and Massively FTL+.
For this reason we cannot properly scale the characters within those fictions to Sora or other keyblade wielder displayed at their peaks, unless they have broken free from the constraints of their own stories and are travelling the worlds freely, such as is the case with Pete and Maleficent or King Mickey, Donald and Goofy.
For more information on the Heartless, Nobodies, Unversed and Dream Eaters, see here.
Supporters and Opponents of the Series
The real cal howard