The series consists of seven games across multiple video game consoles, and future titles are planned. Most of the games in the series have been both critically acclaimed and commercially successful, As of October 2013, the Kingdom Hearts series has sold over 25 million copies worldwide. A wide variety of related merchandise has been released along with the games, including soundtracks, figurines, companion books, novels and manga series.
Kingdom Hearts is the first game in the series, released in Japan on March 28, 2002 for PlayStation 2. Tetsuya Nomura served as game director, his first time in this position. Kingdom Hearts introduced the main characters (Sora, Kairi and Riku) of the series, and established the plot's framework involving hearts and dark beings known as the Heartless. It also established the role of Disney characters in the series, with character cameos from the Final Fantasy series. Kingdom Hearts was released in North America on September 17, 2002, and featured additional content that was not in the original Japanese version. The game was later re-released exclusively in Japan as Kingdom Hearts Final Mix on December 26, 2002.Final Mix includes the content from the North American release and additional enemies, cutscenes, and weapons.
Kingdom Hearts: Chain of Memories is a direct sequel to the first game. It was released on the Game Boy Advance in Japan on November 11, 2004.Chain of Memories was touted as a bridge between the two PlayStation 2 titles, introducing and previewing plot elements that would be explored in the next game. The gameplay system is a departure from the original and employs card game mechanics in real time. Players construct decks out of cards that correspond to different actions in battle, such as attacking or using magic. It was remade into a PlayStation 2 game titled Kingdom Hearts Re:Chain of Memories, which contains polygonal graphics instead of the sprites used in the original game. The remake was released in Japan as a second disc packaged with Kingdom Hearts II Final Mix on March 29, 2007, and in North America as a standalone title on December 2, 2008.
Kingdom Hearts II takes place one year after the events of Chain of Memories. It was released for the PlayStation 2 in Japan on December 22, 2005. The game further explores the "heart" concept by involving a new group of enemies, the Nobodies, which are the cast-off shells of those who have become Heartless. The gameplay is similar to that of the first Kingdom Hearts game, with the addition of the Reaction Command, which performs context-sensitive actions in battle. Kingdom Hearts II was revised into Kingdom Hearts II Final Mix, which contains more material than the original release, such as additional cutscenes and bosses. Kingdom Hearts II Final Mix was released with Kingdom Hearts Re:Chain of Memories in a collection titled Kingdom Hearts II Final Mix+, which was released in Japan on March 29, 2007.
Kingdom Hearts Coded is an episodic mobile phone game that picks up directly after Kingdom Hearts II. The "preinstall" episode was released exclusively in Japan on November 18, 2008 and eight episodes were released between June 3, 2009 and January 28, 2010. The game was remade for the Nintendo DS as Kingdom Hearts Re:coded, and features updated gameplay combining that of two later titles in the series, 358/2 Days and Birth by Sleep. Unlike the original version, Re:coded was released internationally: October 7, 2010 in Japan; January 11, 2011 in North America; and January 14, 2011 in Europe.
Kingdom Hearts 358/2 Days was released for the Nintendo DS in Japan on May 30, 2009. It is primarily set between Kingdom Hearts and Kingdom Hearts II, focusing on Roxas' time in Organization XIII and his motives for leaving. It is the first game in the series to feature cooperative multiplayer in addition to the traditional use of AI-controlled partners. Gameplay is mission-based with optional objectives that yield additional rewards. The game also has a unique panel system which governs character improvement, special abilities, and equipped weapons.
Kingdom Hearts Birth by Sleep is a prequel to the series, released for the PlayStation Portable in Japan on January 9, 2010, and in North America on September 7, 2010 with additional content. The game is set ten years before the events of the first Kingdom Hearts game, revealing the origins of the villain, Xehanort. It consists of four scenarios, three of which focus on one of the game's three protagonists, Terra, Ventus and Aqua. The game was re-released exclusively in Japan under the title Kingdom Hearts Birth by Sleep Final Mix on January 20, 2011 with the content from the English versions as well as new features, such as an additional fifth scenario.
Kingdom Hearts 3D: Dream Drop Distance was released on March 29, 2012 in Japan for the Nintendo 3DS. The game focuses on Sora and Riku's Mark of Mastery exam under Yen Sid in anticipation of Xehanort's return and their subsequent conflicts with enemies from their past. In addition to similar systems inherited from Birth by Sleep, this game features "Dream Eaters" which serve as both enemies and allies. Players may collect and breed friendly Dream Eaters and train them to become more powerful. The English edition came out on July 20, 2012 in Europe while it came out on July 31, 2012 for North America.
Kingdom Hearts χ: At Tokyo Game Show 2012, Square Enix announced Kingdom Hearts χ, previously known as 'Kingdom Hearts for PC Browsers'. It is a browser game for PCs, and is only playable in Japan since July 18, 2013. It features cartoon-like 2D models and is a prequel to the entire series, taking place during the Keyblade War. An international port of the game, Kingdom Hearts: Unchained χ, was released for Android and iOS devices featuring content from the original game's release.
A Kingdom Hearts game was developed exclusively for V CAST, Verizon Wireless's broadband service, and was released on October 1, 2004 in Japan and on February 4, 2005 in the United States. It was one of the launch games for the V CAST services. The game, developed by Superscape and published by Disney Mobile with no involvement from Square Enix, features gameplay akin to the first Kingdom Hearts game, modified for the input method of mobile phones. The game's storyline features Sora struggling to free himself from a nightmare induced by Maleficent's magic.
Kingdom Hearts Mobile is a Kingdom Hearts-themed social game in which players can play mini-games together. Unlike Kingdom Hearts for the V CAST and Kingdom Hearts Coded, this game does not have a storyline and focuses more on socializing. The service operates in conjunction with Kingdom Hearts Coded—new avatar costumes become available after the player completes an episode of Kingdom Hearts Coded. Kingdom Hearts-related media such as wallpapers, ringtones, graphics, and other items can be purchased and downloaded through the service for mobile phones.
Kingdom Hearts HD 1.5 Remix was released for the PlayStation 3 in Japan on March 14, 2013. The collection includes remastered versions of Kingdom Hearts Final Mix and Re:Chain of Memories, which include gameplay enhancements and trophy support. In addition, a "Theatre Mode" has been added, consisting of high definition cutscenes from Kingdom Hearts 358/2 Days. The collection was released in North America on September 10, 2013 in Australia on September 12, 2013, and in Europe on September 13, 2013.
Kingdom Hearts HD 2.5 Remix: After the announcement of HD 1.5 Remix, Nomura stated that it would be "pretty unnatural" if Kingdom Hearts II did not receive an HD update. In the credits of HD 1.5 Remix, clips of Kingdom Hearts II Final Mix, Kingdom Hearts Birth by Sleep Final Mix and Kingdom Hearts Re:coded were shown, hinting at another collection. On October 14, 2013, the collection was announced exclusively for the PlayStation 3, and will include the previously mentioned games, with Re:coded appearing as HD cinematics, similar to 358/2 Days in HD 1.5 Remix. The collection was released in Japan on October 2, 2014, North America on December 2, 2014, Australia on December 4, 2014, and Europe on December 5, 2014.
Kingdom Hearts Collector's Pack: HD 1.5 + 2.5 Remix: The Collector's pack features both Kingdom Hearts HD 1.5 Remix and Kingdom Hearts HD 2.5 Remix, a code to get an Anniversary Set for Kingdom Hearts χ, music, and a booklet with art from the series, with a release in Japan.
After Kingdom Hearts 3D: Dream Drop Distance, Nomura explained that Square would announce a new Kingdom Hearts game with the staff currently working on it. Moreover, Nomura denied rumors that there would be a sequel to Birth by Sleep or an updated version of Dream Drop Distance. Though Kingdom Hearts III will be the end of the "Dark Seeker Saga" centered on Xehanort, it has already been decided where certain characters will end up, in order to potentially continue their story in future games.
Kingdom Hearts HD 2.8 Final Chapter Prologue: In the credits of HD 2.5 Remix, clips of Kingdom Hearts 3D: Dream Drop Distance were shown as well as the inclusion of a secret ending related to the game, hinting at a possible additional collection. In September 2015, Square Enix announced Kingdom Hearts HD 2.8 Final Chapter Prologue. The collection features an HD remaster of Dream Drop Distance as well as Kingdom Hearts χ Back Cover, set to tell the tale of the Foretellers and reveal new parts of the series' history in HD cinematics, and Kingdom Hearts 0.2: Birth by Sleep–A Fragmentary Passage, a new part of the story taking place after the events of the original Birth by Sleep, told from the perspective of Aqua. It will be released worldwide in December 2016.
Kingdom Hearts III: In an interview on September 14, 2010, Tetsuya Nomura stated that his team was too busy with other projects such as Final Fantasy XV (known as Final Fantasy Versus XIII at the time) to work on Kingdom Hearts III. He also stated that his team was doing research concerning the high-definition graphics of the game, and depending on the technical requirements of the next generation consoles. On June 10, 2013, at the E3 Sony press conference, after years of rumors and speculations, Nomura introduced a teaser for Kingdom Hearts III, which stated it was in development for the PlayStation 4. It was announced the next day to be in development for the Xbox One as well. In Kingdom Hearts III, the series protagonist Sora will search for the "Key to Return Hearts" while Sora's friends, Riku and King Mickey, search for Keyblade wielders. The game will conclude the "Dark Seeker Saga", but it will not be the final game in the series.
Both Square Enix and Disney have released a wide variety of Kingdom Hearts merchandise including toys, figurines, clothing, and jewelry. Two of the games, Kingdom Hearts and Kingdom Hearts II, had a soundtrack released to coincide with the video games. These were followed by a nine CD complete set which featured both soundtracks and unreleased tracks.Kingdom Hearts has been adapted as a trading card game by the Tomy corporation of Japan. An English version of the game was released in November 2007 by Fantasy Flight Games. The video games have also been adapted into manga and novel series.
Like the Final Fantasy games, a series of Ultimania books were released in Japan for many of the games. These books include game walkthroughs, interviews, and extra information from the developers. Kingdom Hearts -Another Report- was released along with Kingdom Hearts II Final Mix+ and features game information, visuals by Shiro Amano, and a director interview. In North America, Brady Games released strategy guides for each game. For Kingdom Hearts II, they released two versions, a standard version and a limited edition version. The limited edition was available in four different covers and included a copy of Jiminy's Journal along with 400 stickers.
A manga based on the Kingdom Hearts storyline has been released in Japan and the United States. The story and art are done by Shiro Amano, who is also known for his manga adaptation of the Legend of Mana video game. The story follows the events that took place in the video games with differences to account for the loss of interactivity a video game provides. The manga was originally serialized in Japan by Square Enix's Monthly Shōnen Gangan and eventually released in tankōbon format. The first tankōbon was released in Japan in October 2003. The manga was released in the USA by Tokyopop two years later in October 2005. Yen Press now holds the rights to publish the books for the USA market. The first series, Kingdom Hearts, consists of four volumes, while the second series, Kingdom Hearts: Chain of Memories, has two volumes. The third series, Kingdom Hearts II, has had five volumes published and is currently on hiatus. A fourth series based on Kingdom Hearts 358/2 Days is being serialized. The games have also been adapted as a light novel series, written by Tomoco Kanemaki and illustrated by Shiro Amano. Like the manga series, it is divided into separate series based on the games. Kingdom Hearts is divided into two volumes; "The First Door" and "Darkness Within".Kingdom Hearts: Chain of Memories is divided into two volumes. Kingdom Hearts II is divided into four volumes; "Roxas—Seven Days", "The Destruction of Hollow Bastion", "Tears of Nobody", and "Anthem—Meet Again/Axel Last Stand".
Kingdom Hearts features a mixture of familiar Disney and Square Enix characters, as well as several new characters designed and created by Nomura. In addition to original locations, the Kingdom Hearts series features many worlds from Disney films. Sora must visit these worlds and interact with various Disney characters to protect them from enemies. Often, his actions in these worlds closely follow the storylines of their respective Disney films. The main characters try not to interfere with the affairs of other worlds, as it could negatively affect the universe's order.Moogles, small creatures from the Final Fantasy series, are another common element in the games. They provide the player with a synthesis shop in order to create and purchase items used in the game. So far, twenty-one characters from the Final Fantasy Series have appeared in the Kingdom Hearts games. The main cast from The World Ends with You also makes an appearance in the series as seen in Dream Drop Distance.
The series starts with Kingdom Hearts showing how a 14-year-old boy named Sora is separated from his friends Riku and Kairi when their world, Destiny Islands, is invaded by creatures known as the Heartless. During the invasion, Sora obtains a weapon called the Keyblade that allows him to fight the Heartless. He soon arrives in another world, Traverse Town, where he meets Donald Duck and Goofy, two emissaries from Disney Castle sent by King Mickey to find the wielder of the Keyblade. The three band together and travel to different Disney-themed worlds, sealing the hearts of the worlds to prevent more Heartless invasions, and to find Riku and Kairi. Along the way, they encounter a group of Disney villains led by Maleficent, who are controlling the Heartless to capture seven maidens called the "Princesses of Heart", and use their power to open the door to "Kingdom Hearts" and rule over all the worlds. Though they eventually defeat Maleficent, the three discover that Ansem has been possessing Riku's body and using Maleficent, and plans to attain eternal darkness by opening Kingdom Hearts himself. Sora, Donald and Goofy defeat Ansem, and seal the door to Kingdom Hearts with the help of Riku and King Mickey on the other side of the door. Kairi remains back home to await her friends' return.
In Kingdom Hearts: Chain of Memories, Sora and his two friends begin searching for Riku and King Mickey. They arrive at a fortress called Castle Oblivion, where they encounter members of a mysterious group called Organization XIII, which is made up of non-existent beings called the Nobodies. While in the castle, the three's memories are manipulated by a girl named Naminé. After defeating the Organization, the three are put to sleep for a year by Naminé to allow them to regain their memories, though they must lose the memories of their experience in Castle Oblivion. Meanwhile, Riku appears in the basement of the castle and travels up to the surface with the aid of Mickey. Riku then keeps Sora and Naminé safe until Sora is awoken. In Kingdom Hearts 358/2 Days, a snag in the plan over the year forces Riku to capture Roxas, the thirteenth member of the Organization, in order to enable Sora's reawakening.
In Kingdom Hearts II, Sora and friends awaken from their sleep and resume their search for Riku and King Mickey, passing through Twilight Town and meeting Yen Sid, learning of the Nobodies and becoming re-familiarized with Organization XIII. Sora once again travels to many Disney-themed worlds and resolves the trouble caused by the Heartless and Nobodies, and Maleficent's servant Pete. They reunite with King Mickey and encounter Xemnas, the leader of Organization XIII. The Organization's plan is also revealed—they seek the power of "Kingdom Hearts", the sum of all the hearts that Sora released by destroying the Heartless with his Keyblade, to regain their lost hearts. The three arrive at the headquarters of Organization XIII and team up with their friends and Kairi, who went to find Sora earlier. Ansem the Wise uses a device that dissipates some of Kingdom Hearts' power, but it self-destructs, engulfing Ansem. At the top of the Castle that Never Was, Sora and his friends battle Xemnas. After Sora and Riku defeat Xemnas, they get trapped in the Realm of Darkness, but a letter from Kairi summons a gateway for them and the two are reunited with their friends at their home.
Sometime later, Sora, Riku and Kairi receive a letter from King Mickey's detailing parts of their past that Naminé learned while restoring Sora's memory, and Mickey found out about during the events of Kingdom Hearts Coded. As they read the letter, they learn about the exploits of the three Keyblade wielders' fates during the events of Kingdom Hearts Birth by Sleep (a decade before Kingdom Hearts) by the hands of Xehanort while trying to recreate the legendary χ-blade which all Keyblades are modeled after and plunge the worlds into chaos: Terra is converted by Xehanort's experiments to turn his heart into "Ansem" and his body into Xemnas; Ventus sacrifices himself to stop Xehanort's plan to obtain the χ-blade, and his heart ended up with the body of Sora himself, and new Keyblade Master Aqua ends up trapped in the Realm of Darkness after sacrificing herself to save Terra. King Mickey also discovers that the destruction of "Ansem" and Xemnas has led to the reconstruction of Xehanort. To combat the new threat Xehanort poses, Sora and Riku take an exam to attain the Mark of Mastery that will allow them to become Keyblade Masters themselves.
During the test in Kingdom Hearts: Dream Drop Distance, Sora and Riku enter into the Realm of Sleep, where they encounter a young version of Xehanort with the ability to travel through time. The two Keyblade wielders also learn of Xehanort's true goal: creating thirteen replicas of himself by placing a piece of his own heart in each "host", thus taking it over, then pitting them against seven hearts of pure light in an ultimate battle to recreate the χ-blade once more. Though the Organization was defeated, Xehanort had a second plan to become "Ansem" and give give his younger self the ability to travel through time and gather other versions of Xehanort together to form the Thirteen Seekers of Darkness. Sora is narrowly saved from becoming Xehanort's final vessel, and Riku learns that data was implanted in Sora during his year-long sleep that may be able to be used to save both those who are lost and ceased to be. At the end of the exam, Riku is declared a Keyblade Master, and Sora embarks on a new journey alone to train. In the meantime, to defend the Princesses of Heart from Xehanort, the Seven Guardians of Light are formed from any available Keyblade users (including Kairi) to combat the Thirteen Darknesses in the upcoming final battle against Xehanort.
The Kingdom Hearts games contain elements of both action and role-playing video games. The games are driven by a linear progression from one story event to the next, usually shown in the form of a cutscene, though there are numerous side quests available that provide bonus benefits to the characters. In most games, the player primarily controls the principal protagonist of the series, Sora. Sora is usually accompanied by Donald Duck and Goofy, who are artificial intelligence-controllednon-playable characters that aid Sora in battle. In the first and third game, their behavior can be altered to suit different combat objectives. The games feature real-time combat that incorporates physical attacks, magic, and summonings, though each game handles battles differently. The game also allows for items to be used on the field of battle to heal oneself or one's party members.
Gummi Ships are another common element of the series, which serve as the main mode of transportation between worlds in the games. The gameplay for the Gummi Ship sections is more akin to a rail shooter. Because it received negative criticism in the first game, it was modified in the third title. Most games also feature a journal which is accessible from the main menu. This journal keeps track of information regarding the story, characters, enemies, and locations. In the first three games, the journal is kept by Jiminy Cricket, who was appointed by Queen Minnie as the royal chronicler. In 358/2 Days, Birth by Sleep and Dream Drop Distance, the main characters write their own journal entries.
A battle in the first Kingdom Hearts game
The games are influenced by their parent franchise, Final Fantasy, and carry its gameplay elements over into their own action-based, hack-and-slash system. Like many traditional role-playing games, Kingdom Hearts features an experience point system which determines character development. As enemies are defeated, the player gains experience which culminates in a "level-up", where the characters grow stronger and gain access to new abilities. The amount of experience is shared with all party members and each character grows stronger as experience is gained.
The music for the series has been primarily composed by Yoko Shimomura. Kaoru Wada works as the arranger for orchestral music, including orchestral renditions of the main vocal themes and the ending themes. The orchestral music was performed by the New Japan Philharmonic Orchestra and the Tokyo Philharmonic Orchestra. Soundtracks were released for the first and third installments following the release of their respective games. A compilation soundtrack was later released that included soundtracks for the entire series, including reworked tracks for the re-released Kingdom Hearts Re:Chain of Memories.
While the themes for some of the Disney-based worlds are taken directly from their Disney film counterparts, most of them are given entirely original musical scores. In addition to each world having unique background music, each is given its own battle theme rather than having a common theme to cover all fights. Several of the main characters have themes, and the final boss of each game has several themes played in the various phases of those fights. The fights with Sephiroth feature a modified version of Nobuo Uematsu's "One-Winged Angel" from Final Fantasy VII.
The main theme songs for the Kingdom Hearts games were written and performed by Japanese pop star, Hikaru Utada. The two main themes are "Hikari", from Kingdom Hearts and Chain of Memories, and "Passion", from Kingdom Hearts II. Each song has an English counterpart, "Simple and Clean" and "Sanctuary" respectively, for the North American and European releases. Utada was the only singer Tetsuya Nomura had in mind for the first Kingdom Hearts theme song. This marked the first time Utada had produced a song for a video game. Both theme songs reached notable popularity in Japan. On weekly Oricon charts, "Hikari" reached No. 1 in 2002 and "Passion" reached No. 4 in 2005.
The initial idea for Kingdom Hearts began with a discussion between Shinji Hashimoto and Hironobu Sakaguchi about Super Mario 64. They were planning to make a game with freedom of movement in three dimensions like Super Mario 64 but lamented that only characters as popular as Disney's could rival a Mario game. Tetsuya Nomura, overhearing their conversation, volunteered to lead the project and the two producers agreed to let him direct. A chance meeting between Hashimoto and a Disney executive in an elevator—Square and Disney had previously worked in the same building in Japan—allowed Hashimoto to pitch the idea directly to Disney. Development began in February 2000 with Nomura as director and Hashimoto as producer. While Nomura had done previous work in the Final Fantasy series as monster designer and graphic director, he did not gain widespread recognition until he was the lead character designer for Final Fantasy VII. Kingdom Hearts marked his transition into a directorial position, though he also served as the game's character designer. Scenarios were provided by Kazushige Nojima who was a scenario writer for Square from Final Fantasy VII until he left in 2003. Originally the development focused on the gameplay with a simple story to appeal to Disney's target age range. After Kingdom Hearts executive producer Hironobu Sakaguchi told Nomura the game would be a failure if it did not aim for the same level as the Final Fantasy series, he began to develop the story further. In June 2013, Nomura stated the name of the game came from him thinking about Disney Theme Parks, especially Animal Kingdom. However, Nomura could not get the IP with just "Kingdom", so the development team began to think about "heart" as a core part of the story, so they decided to combine the two to form "Kingdom Hearts".
Nomura placed a secret trailer in Kingdom Hearts in hopes that fans would want a sequel. He was unsure if fans would want a sequel and felt that if they did not, then it would be best to leave certain events in the first game unexplained. After Kingdom Hearts Final Mix was completed, development for Kingdom Hearts II began. There were several obstacles to clear before development could begin on a sequel. One was the development team's desire to showcase Mickey Mouse more; Mickey's inclusion in the first game was restricted to a very small role. Nomura had planned for the sequel to take place a year after the first and originally intended for the events of that year to be left unexplained. To bridge the gap between the two games, Kingdom Hearts: Chain of Memories was developed. Nomura was hesitant about releasing a game on the Game Boy Advance because he felt the 3D graphics of the original game would not translate well into 2D. He changed his position after hearing that children wanted to play Kingdom Hearts on the handheld system.
Though Disney gave Nomura freedom in the characters and worlds used for the games, he and his staff tried to stay within the established roles of characters and boundaries of the worlds. Nomura has stated that though many of the Disney characters are not normally dark and serious, there were not many challenges making them so for the story, and despite this, their personalities shine because they maintain their own characteristics. He also felt managing and keeping multiple worlds was problematic. When deciding which worlds to include in the game, the development staff tried to take into account worlds with Disney characters that would be interesting and made an effort to minimize any overlap in the overall look and feel of each world.
The inclusion of specific Final Fantasy characters was based on the opinions of both fans and staff. Another criterion for inclusion was whether the staff felt the characters would fit into the storyline and in the Kingdom Hearts universe. Initially, Nomura was hesitant to use characters he did not design, because he was unfamiliar with the backstory of such characters. For Kingdom Hearts II, he changed his mind after receiving pressure from his staff. Throughout the development of the games, Nomura has often left certain events and connections between characters unexplained until the release of future games. Nomura does this because he feels that games should have room for fans to speculate and use their imagination. He has stated that with speculation, even though a game gets old, people can still be happy with it.
The first Kingdom Hearts was announced at E3 in May 2001. Initial details were that it would be a collaboration between Square and Disney Interactive, and would feature worlds developed by both companies and Disney characters. New characters were designed by Nomura and include Sora, Riku, Kairi, and the Heartless. On May 14, 2002, a press release announced a list of the English voice actors. The list included Haley Joel Osment, David Gallagher, and Hayden Panettiere as the three new characters introduced into the game. It was also announced that many of the Disney characters would be voiced by the official voice actors from their respective Disney films.
A secret trailer in the first Kingdom Hearts and Kingdom Hearts Final Mix hinted at the possibility of a sequel. Rumors for a sequel on the PlayStation 2 were spurred in Japan when a Japanese video game site, Quiter, stated that "an internal (and anonymous) source at Square Japan" confirmed that development of Kingdom Hearts II had begun. It was not until Kingdom Hearts II was announced, along with Kingdom Hearts: Chain of Memories, at the Tokyo Game Show in September 2003 that rumors were confirmed. Initial details were that it would take place some time after Kingdom Hearts: Chain of Memories, which takes place directly after the first game. Other details included the return of Sora, Donald, and Goofy, as well as new costumes. At the 2004 Square Enix E3 press conference, the producer, Shinji Hashimoto, stated that many mysteries of the first game would be answered.
To help market the games, websites were set up for each game and demos were on display at gaming events. Each game in the main series was also re-released in Japan with additional content and served as canonical updates to the series. The additional content foreshadowed later plot elements in the series. The rereleases of the main series games had the term "Final Mix" added after the title, while Kingdom Hearts: Chain of Memories and Kingdom Hearts Coded were re-released as Kingdom Hearts Re:Chain of Memories and Kingdom Hearts Re:coded and released on the PlayStation 2 and Nintendo DS, respectively, with 3D graphics, voice overs during some cutscenes, and new game content.
The Kingdom Hearts series has been critically and commercially successful. As of March 2014, the series has sold over 20 million copies worldwide. The three main games in the series all met with positive sales at the time of their releases. In the first two months since the North American release of Kingdom Hearts, it was one of the top three highest-selling video games.Chain of Memories sold 104,000 units in 48 hours in Japan, a record for a Game Boy Advance title at the time. Its positive debut sales placed it in the top spot of sales charts in Japan. In the first month of its North American release, it was ranked 1st on GameSpot's ChartSpot for portable systems and 6th for all consoles. Within three days of the Kingdom Hearts II release in Japan, it shipped 1 million copies, selling through within a month. By the end of March 2006, the NPD Group reported that Kingdom Hearts II was the highest-selling console game in North America, with 614,000 copies. In the month after its release in North America, Kingdom Hearts II sold an estimated 1 million copies.
The games have also received high ratings and positive comments from reviewers. All of the main games in the series have scored a 36 out of 40 or higher from the Japanese gaming magazine Famitsu, known for its harsh grading. All six games have been praised for their visuals. Game Informer considers the series the eleventh "must-play PlayStation 2" series. The individual games have also won several awards. GameSpot commented that the concept of mixing the serious elements of Final Fantasy with the lighter elements of Disney seemed impossible, but was pulled off quite well. Because of that they awarded Kingdom Hearts "Best Crossover Since Capcom vs. SNK" in their 2002 Best and Worst of the Year awards.IGN named Kingdom Hearts "Best Art Style/Direction" in their 2003 list of "Best Looking Games on PS2".G4 awarded it "Best Story" at their 2003 G-Phoria awards show.Electronic Gaming Monthly awarded Kingdom Hearts II "Best Sequel" of 2006. It tied with Resident Evil 4 as Famitsu's Game of the Year 2005. The manga series has also been well received. Several of the manga volumes were listed on USA Today's "Top 150 best sellers". The highest ranked volume was Kingdom Hearts volume 4 at #73. Every volume listed stayed on the list for at least two weeks; Kingdom Hearts volume 4 stayed the longest at four weeks.
^King Mickey's Note: Donald, Sorry to rush off without sayin' goodbye, nevertheless, there's big trouble brewin'. Not sure why, but the stars have been blinkin' out, one by one. And that means disaster can't be far behind. I hate to leave you all but I've gotta go check into it. There's someone with a "key" — the key to our survival. So I need you and Goofy to find him, and stick with him. Got it? We need that key or we're doomed! So go to Traverse Town and find Leon. He'll point you in the right direction. P.S. Would ya apologize to Minnie for me? Thanks, pal. Square (November 15, 2002). Kingdom Hearts. PlayStation 2. Square Electronic Arts.
^Marluxia: The moment you set foot in this castle, you forgot every spell and ability you ever know. In this place, to find is to lose and to lose is to find. That is the way in Castle Oblivion. Square Enix (December 2, 2008). Kingdom Hearts Re:Chain of Memories. PlayStation 2. Square Enix U.S.A., Buena Vista Games.
^Jiminy: So you can put 'em back together? / Naminé: Yes, but first I have to undo the chains of memories I made on my own. After I've done that, I have to gather up the memories scattered across each of your hearts and them reconnect them. It might take some time. But I think it might work. No—It will work. I'm sure. It's my turn to look after you. / Sora: All right. We all really trust you. / Jiminy: Oh... Wait just a second! You said you'd have to undo the links you made. But that means— / Naminé: Yes. You won't be able to remember anything about what happened here. / Sora: Not even you? / Naminé: I'm sorry. It's the only way, I'm afraid. Square Enix (December 2, 2008). Kingdom Hearts Re:Chain of Memories. PlayStation 2. Square Enix U.S.A., Buena Vista Games.
^Mickey: But, what you actually fought was his Heartless. Ya see, he wasn't really Ansem. He just went around telling everybody that he was. Square Enix (March 28, 2006). Kingdom Hearts II. PlayStation 2. Square Enix U.S.A., Buena Vista Games.
^Mickey: Now I remember! Xehanort! Ansem's apprentice! The leader of Organization XIII is Xehanort's Nobody! Square Enix (March 28, 2006). Kingdom Hearts II. PlayStation 2. Square Enix U.S.A., Buena Vista Games.
^Ansem the Wise: It's a device to reclaim Kingdom Hearts and encode it as data. / Mickey: Not sure I get it. / Ansem the Wise: I do not claim to know the outcome of this venture, either. After all...Hearts are unpredictable. Square Enix (March 28, 2006). Kingdom Hearts II. PlayStation 2. Square Enix U.S.A., Buena Vista Games.
^Xemnas: Heed me, Kingdom Hearts! Lend me your power, so that we may be complete! The power to erase the fools that hinder us. Square Enix (March 28, 2006). Kingdom Hearts II. PlayStation 2. Square Enix U.S.A., Buena Vista Games.
^Sora: W-We're back. / Kairi: You're home. Square Enix (March 28, 2006). Kingdom Hearts II. PlayStation 2. Square Enix U.S.A., Buena Vista Games.
^Minnie: Oh, and to chronicle your travels, he will accompany you. / Jiminy: Over here! Cricket’s the name. Jiminy Cricket, at your service. Square (November 15, 2002). Kingdom Hearts. PlayStation 2. Square Electronic Arts.