Mickey Mouse in Kingdom Hearts

King Mickey, often referred to as The King, Your Majesty, or simply Mickey Mouse, is the king of Disney Castle and a recurring character in the Kingdom Hearts series. He travels the worlds battling the forces of darkness and is a Keyblade Master, and the chosen Keyblade wielder for the Realm of Darkness, though he follows the path of light. Originally believing that the darkness had to be eliminated, he eventually realized that light and darkness are interdependent and cannot exist without the other due to his encounters with Riku.

Originally a ship's hand working with Captain Pete at Timeless River, Mickey eventually became a student of the Keyblade Master Yen Sid. Mickey was a main player in the conflict with Master Xehanort, and was later one of the first to notice the threat of the Heartless, inventing the first Gummi Ship to travel to other worlds in order to work against the monsters.

Before Kingdom Hearts Birth by Sleep
When he was young, Mickey worked as a deck hand with his captain, Pete. He and Pete sailed the steamboat Willie throughout Timeless River. This past association causes Pete to refer to Mickey as "the Boat-Boy King."

When Sora comes from the future using a door in the Hall of the Cornerstone, he, along with the future versions of Donald Duck and Goofy, mistake Mickey for being himself from the future. Four times, Mickey appears at scenes of trouble, either in peril (or appearing to be so), saving the day, or both. On one such occasion, his house is attacked by hordes of Heartless and a mini black hole that sucks up all his furniture. After each time Sora helps him out, Mickey shakes his hand and leads him to another scene of peril.

Kingdom Hearts Birth by Sleep
While Terra, Ventus, and Aqua search for Master Xehanort and Vanitas, King Mickey undergoes the Mark of Mastery Exam under the supervision of Yen Sid at the Mysterious Tower, accompanied by Donald and Goofy, during which he uses the Star Seeker Keyblade. Later on, Mickey runs away without Yen Sid´s permission, using a Star Shard that allows him to travel throughout other worlds; however, it works rather randomly, as he has not learned how to control it. Terra witnesses the King's leave when he first visits the tower.

Upon visiting the Mysterious Tower, Terra watches Mickey's Star Shard take him to the Keyblade Graveyard. The Star Shard knew that Mickey needed to be there to save Ventus. When Ventus loses a fight with Vanitas, he steps in to help. They successfully drive him off before Mickey's Star Shard brings them to Radiant Garden. He later teams up with Aqua (after Ven attempts to get inside the Radiant Garden castle), rescuing a young Kairi from the Unverseds' attempt to capture her. He is whisked off to Neverland when the battle ends, telling Aqua to not worry about him.

While exploring Neverland Mickey is ambushed by Vanitas and knocked unconscious, who then proceeds to kidnap Mickey and take him to the Keyblade Graveyard. Ven tries to help Mickey when he finds out about it, only for them to both get sucked into a vortex. Mickey is left stranded in space before Aqua finds him and takes him back to the Mysterious Tower.

Upon regaining consciousness, Mickey returns to the Keyblade Graveyard, where he helps Aqua battle Ventus, who is possessed by Vanitas, and eventually guides them to the Mysterious Tower, where they discover that Ventus's heart has left his body. Later, after Aqua leaves with Ventus to find him a safe place, Mickey sorrowfully hands in the Star Shard and his Star Seeker Keyblade, thinking he has failed to reach his goal and disappointed his master, and begins to leave. Before he departs, however, Master Yen Sid hands him back the Keyblade with a smile, showing him that he is indeed worthy of the title of Keyblade Master. Mickey then happily accepts it.

Between Kingdom Hearts Birth by Sleep and Kingdom Hearts
After the barriers between the worlds shatter, causing meteors to fall from the sky, Mickey realizes the threat that the Darkness presents. Mickey seeks help for his concerns and the danger he expects. By using the material from the meteors themselves to make a Gummi Ship, Mickey travels to Radiant Garden and meets Ansem the Wise. Mickey befriends Ansem and tells him of his concern about the growing Darkness between the worlds. It is also here that Mickey meets Xehanort, who seemingly disturbs the King.

Sometime during these years, Scrooge and Mickey traveled together to create a transit system.

Kingdom Hearts
King Mickey leaves his home, Disney Castle, leaving a note instructing Donald and Goofy to "find the Key". King Mickey arrives in Traverse Town at the same time as Sora, but keeps himself out of sight. Pluto follows him through a Corridor of Darkness into the Realm of Darkness, where Mickey finds the Keyblade of the Realm of Darkness needed to seal the Door to Darkness. By the time the Final Keyhole was opened, Mickey finds Riku, whose body had been stolen by Ansem, Seeker of Darkness, and quickly becomes allies with him. After the defeat of Ansem, he helps Sora to seal Kingdom Hearts to prevent the Heartless from escaping through it. Although Sora is reluctant to leave Mickey and Riku trapped within the Realm of Darkness, Mickey assures them that there will always be a door to the light, and thanks Donald and Goofy for their loyalty.

Kingdom Hearts: Chain of Memories
Although Sora, Donald and Goofy initially enter Castle Oblivion believing the King to be there, Mickey is only able to send a bit of his light to help Riku in the twelfth basement, when he is attacked by Ansem. When Riku enters the eleventh basement, Mickey is able to project an image of himself, and he makes Riku promise to keep fighting the darkness, while promising to find a way to where Riku is. Riku is then able to call upon Mickey's power in battle as he ascends through the castle's basements.

When Ansem attempts to possess Riku after his fight with Lexaeus in the B4F Exit Hall, Mickey sends his light to drive him off. After Riku emerges from the third basement, Ansem takes advantage of Riku's acceptance of his own darkness to attempt possessing him once again. Mickey's light drives Ansem off once more, and Mickey arrives in person, explaining to Riku that a World Card, leading to Twilight Town, had appeared before him and showed him a path from the Realm of Darkness to where Riku was. Mickey meets Riku at the B2F Exit Hall, happy to see Riku chose not to be put to sleep by Naminé, and they speak with DiZ, who seems familiar to Mickey.

Mickey accompanies Riku to the entrance to the first basement, where Riku intends to face Ansem once and for all. Riku asks Mickey to let him face Ansem alone, and he tries to get Mickey to promise to destroy him if Ansem possesses him again. Mickey refuses and promises instead to rescue Riku, no matter what. After Ansem is defeated, Mickey rescues Riku from the sudden rush of darkness and takes him to the castle's entrance hall. He calms Riku's concerns about the remnants of darkness in his heart by pointing out that Riku's darkness is his own to control, explaining that although he used to think darkness was only bad, he is fascinated by Riku's ability to use light and darkness together and wants to accompany Riku along his chosen path. When Riku thanks "[his] Majesty", Mickey laughs and says that, as a friend, Riku can just call him "Mickey".

Mickey and Riku leave the castle, wearing the black coats given to them by DiZ, who they encounter at the crossroads. He asks Riku whether he has chosen to follow the roads of light or darkness. Riku instead chooses the "road to dawn", and he and Mickey continue on.

Some time after this, the two of them walk through the Great Maw, where Riku momentarily collapses under the strain of the darkness in his heart. Although a concerned Mickey tries to help, Riku shrugs him off. The two of them eventually split up.

Kingdom Hearts 358/2 Days
King Mickey appears in the Twilight Town woods facing Riku, who has taken on the form of Ansem, Seeker of Darkness. Mickey readies to attack as Riku calmly ties his blindfold into place, and looks shocked at Riku changing appearance. Then Riku makes Mickey promise not to tell Sora what happened to him when he wakes up.

Kingdom Hearts II
Sometime after Riku leaves DiZ's employ, he encounters Mickey and gives him the Munny Pouch that he had stolen from Roxas in the Simulated Twilight Town. Not wanting Sora and Kairi to know about his condition, Riku pleads with Mickey not to reveal his whereabouts or his condition to Sora, and Mickey reluctantly agrees.

Mickey later arrives to help Sora fend off the Nobodies that attacked them in Twilight Town posing as somewhat of a fake Organization XIII member. After the battle, he hands Sora the pouch of munny Riku gave him and instructs him to visit his mentor, Yen Sid, running off afterward. Yen Sid reveals that Mickey's reasons for leaving Disney Castle in the first place was to investigate the mysterious outbreak of Heartless and the more mysterious Organization.

At Hollow Bastion, Mickey reveals the truth about "Ansem", but is reluctant to reveal any information on Riku. He then aides the group in fending off the Heartless that Maleficent has summoned to destroy Radiant Garden. Initially, he orders Sora, Donald, and Goofy to leave Hollow Bastion and leave the Heartless to them, but Donald and Goofy go against his orders when they realize how desperate Sora is to help Leon. He later confronts them after they defeat Demyx, at first appearing angry, but soon simply decides to allow them to help.

When Goofy apparently dies after taking a nasty blow to the head while saving Mickey from the same fate, Mickey swears that the Heartless would pay and permanently discards his Organization XIII disguise. They are later relieved to discover that Goofy was only unconscious. When he and Sora confront Xemnas, he jumps after Xemnas into a corridor of darkness before it closed, thus preventing Sora, Donald and Goofy from going after him, but since he appears later in Twilight Town, it is apparent that he could not follow Xemnas all the way back to the Organization's base.

Sora and the others meet him in Twilight Town, where they find a way into The World That Never Was through the Simulated Twilight Town DiZ had created. When they enter the world, Mickey goes ahead of Sora to look for Ansem the Wise. He eventually finds him, and rescues him from a group of Nobodies. Ansem then attempts to use his machine to convert Kingdom Hearts into data, but was unsuccessful and vanishes when the machine explodes.

Mickey then confronts Xemnas with Sora, Riku, Kairi, Donald and Goofy, and watches as Xemnas opens Kingdom Hearts. Xemnas then blocks out King Mickey and Kairi from participating in the final fight, first by launching a building at him and Kairi, closing the door to Kingdom Hearts, and later closing the dark portal to the Destiny Islands, preventing Mickey, Kairi, Donald, and Goofy from returning to aid Sora and Riku.

After Sora and Riku end the Organization's plot, Mickey waits with Donald, Goofy, and Kairi on Destiny Islands for their return. Once they do, he runs to Riku and congratulates them both for defeating Organization XIII. During the end credits, King Mickey is seen returning with Donald, Goofy, Scrooge McDuck, Huey, Dewey, and Louie, Pluto, and Jiminy to Disney Castle, where he shares a kiss with his wife Queen Minnie.

Soon after, Mickey sends Sora, Riku, and Kairi a bottled letter.

Kingdom Hearts coded
Mickey digitizes Jiminy's Journal to investigate a mysterious message saying: "We must return to free them from their torment". When bugs appear in the digital system, he decides to create a data version of Sora to fix them.

Following the digital Sora's time in Traverse Town, he is attacked by Heartless. After disposing of them with the Star Seeker, he tries to leave the library to check the castle, but finds himself locked in, along with Jiminy, Donald, and Goofy. Somehow, they have been transported into the digital journal itself. While in the journal, he joins forces with Data-Sora and the journal itself (in the form of Riku) to dispatch the Heartless and debug the digital world. After defeating Sora's own Heartless, who was corrupting the journal, Mickey and his friends are returned to the real world when the debugging is completed, but a message claiming that a door to a new world has opened appears on the screen. Preparing for another adventure, Mickey requests to be taken into the digital world again to solve this new mystery.

Inside, he escorts Data-Sora throughout Castle Oblivion until they encounter the data version of Naminé, who tells them about Terra, Ventus, Aqua, and the reason behind the Bug Block corruption, which was caused by the real Naminé when she removed Sora's memories and later restored them.

After everything in the journal was restored, Mickey returns to the real world to write the letter to Sora to tell him about those who need him to heal their sadness, and a new journey is about to begin.

Later, Mickey reports to Yen Sid that he believes he has finally found where Ventus's missing heart is, leaving only Terra's heart to be found. Their discussion quickly shifts towards the topic of Master Xehanort, who Mickey is stunned to learn will return due to the defeat of his Heartless, Ansem, and his Nobody, Xemnas, and the subsequent restoration of Xehanort. Fearing that they may have to fight more than a "single one of Xehanort", Yen Sid orders Mickey to bring Sora and Riku before him so that they may take the Mark of Mastery exam.

Kingdom Hearts 3D: Dream Drop Distance
Mickey is present with Donald and Goofy in the Mysterious Tower as Yen Sid puts Sora and Riku through the Mark of Mastery exam in the Sleeping Worlds. While overseeing it, Mickey receives a note from Maleficent and Pete along with Minnie's crown, ordering him to return to Disney Castle, where he finds them holding Minnie hostage. Maleficent demands that Mickey hand the Datascape over to her, but Mickey refuses. Lea arrives and helps free Minnie. Mickey orders Maleficent to leave, and he and his friends return to the Mysterious Tower.

Later on, when Sora and Riku do not return from the Sleeping Worlds at the expected time, Mickey enters and finds Riku in Where Nothing Gathers, using a Stopza spell to freeze Young Xehanort and help him save the comatose Sora, but Xehanort remains unaffected by the spell and knocks Mickey aside in order to battle Riku. Following the fight, Mickey and Riku meet the revived Master Xehanort, who explains to them the details of his past endeavors and his continuing plans to recreate the χ-blade and restart the Keyblade War. Mickey openly accuses Master Xehanort of ruining the lives of Terra, Aqua, Ven and Master Eraqus, but Xehanort merely quips that it was their destiny. As Master Xehanort prepares to turn Sora into a vessel for a piece of his heart, Xemnas physically restrains Mickey from rescuing him. Lea arrives in time to protect Sora, and Ansem responds by releasing his Guardian, who grabs Mickey and Riku but is knocked out by Donald and Goofy. Master Xehanort and his lackeys retreat, but swear revenge.

Mickey helps bring Sora's body back to the tower, where Riku manages to mend his broken heart and awaken him. Riku is named a Keyblade Master for this and Mickey congratulates his friend, but is shocked when Lea summons his own Keyblade. Later on, Yen Sid tells Mickey of their plans to form a group of seven Keyblade warriors of Light to counter Master Xehanort, and Mickey is visibly stunned when Yen Sid's newest student turns out to be Kairi.

Along their journey, Sora and Riku also cross paths with two past incarnations of Mickey: one as a Musketeer and the other as a Sorcerer apprentice under Yen Sid.

Kingdom Hearts III
Mickey, along with Donald and Goofy will journey along with Sora in Kingdom Hearts III.