Yen Sid

Yen Sid is a powerful sorcerer and teacher of Mickey Mouse, who first appeared in The Sorcerer's Apprentice, a segment of Fantasia. In Kingdom Hearts II, his voice is provided by Corey Burton.

Personality
Being rather mysterious, not to much is known about the sorcerer. He is wise, practical and most often seen with a serious tone. Most who encounter Yen Sid often find him intimidating but underneath his fierce look lies a heart of gold. Surprisingly he is very forgiving and actually has a sense of humor. He is more than aware of Mickey's mischief and willing to deal with this; putting it aside to teach his apprentice.

His past is never looked upon with the exception of the Kingdom Hearts continuity. Years before Sora, the sorcerer was a keyblade wielder but eventually retired or as he puts it "doffed that matle."

Appearance
Yen Sid is an elderly man with his signature sorcerer hat atop his head. He has a long Grey beard reaching down underneath his chest. He has small eyes with tiny pupils as well as a long aqua colored cloak which he wears in all appearances.

Powers and Abilities
Most of Yen Sid's magic is obtained through his sorcerer hat. With the hat he is known conjure up mystic clouds, bring to life inanimate objects. Despite this he has abilities without the hat. When Mickey accidentally flooded the tower with the hat, Yen Sid stormed in and summoned the water to dissolve and while so he created large waves all without the hat. In the Kingdom Hearts series, Yen Sid was able to disappear in the flash of a light. Most other abilities to this day is unknown.

Fantasia
The great sorcerer first appeared in the Fantasia short, The Sorcerer's Apprentice, as Mickey Mouse's master. He was the owner of a magical hat, which is apparently the source of his power. In the short, Yen Sid is preforming magic while a young Mickey Mouse completes his chores. Satisfied with his work, the sorcerer puts down his hat retiring for the night. During his absence, Mickey takes the hat and begins to play with the magic. He creates a living broom and orders it to take water and place it in a fountain (which is Mickey's chore). After falling asleep Mickey awakens to see the broom flooding the tower. Mickey chops up the broom but this only creates several more. The tower is nearly flooded completely until the powerful Yen Sid returns from his chambers and stops the chaos. Mickey returns the hat to his angry master as he slowly goes to finish his chores. Yen Sid shows a small smirk at Mickey, who gives a weak smile and to make sure the apprentice has learned his lesson, the wizard smacks him once in the buttocks with the now inanimate broom, making Mickey get the job done faster.

Fantasia 2000
Yen Sid reappears in the sequel and lives out the same role in the original. His sequence in the Fantasia sequel being the only sequel from the original film to appear in the film.

House of Mouse
In the animated television series House of Mouse, Yen Sid makes a few cameos, usually alongside the magic brooms from the Fantasia short. In the episode "Rent Day" Mickey needs to find a book for Belle and asks Yen Sid for it until he reveals his strict face and Mickey quotes "Never mind." In "House of Christmas", Pete steals the hat from Yen Sid and uses it to control the brooms as they steal everyones Christmas gifts.

The Sorcerer's Apprentice
Yen Sid himself did not appear in the film, although he was the inspiration for the wise sorcerer character Balthazar Blake.

Fantasia Gardens Miniature Golf
Yen Sid can be easily spotted as a statue at the miniature golf activity at Walt Disney World Resort. His statue showcases Yen Sid controlling water as he did in the film.

Kingdom Hearts series
Majority of information taken from Kingdom Hearts Wiki-Yen Sid.

Yen Sid appears in Kingdom Hearts II and Kingdom Hearts Birth by Sleep as a retired Keyblade Master, renowned for his wisdom and command over the arts of magic; though no longer an active Keyblade Master, he still keeps a close watch on the balance between Light and Darkness. He was once Mickey Mouse's master, and taught him everything he knows of magic and the Keyblade.

Kingdom Hearts Birth by Sleep
After training Mickey on the night before Terra and Aqua's Mark of Mastery exam, Yen Sid relays to him a, "feeling that something terrible is about to transpire." The next morning, following the completion of the exam, Yen Sid contacts Master Eraqus via the crystal in the Land of Departure's throne room about the threat of the Unversed.

When Terra visits Yen Sid's tower, he asks him for guidance about Master Xehanort, Vanitas, and the Unversed. After Terra leaves, Yen Sid comments "I had hope Xehanort, your heart would no longer lead you astray". Later, Ventus shows up at his tower with a Star Shard, and Master Yen Sid uses divination magic to locate Mickey. Aqua later returns Mickey to his tower, and Master Yen Sid tells her of Master Eraqus's destruction and that the murder was committed by Master Xehanort and Terra. Sometime after Aqua leaves for the Keyblade Graveyard, Mickey departs to assist her and her friends.

Following the defeat of Vanitas, Mickey returns with Aqua and a comatose Ventus. Master Yen Sid finds himself unable to sense Ven's heart and encourages Aqua to believe in their friendship—which serves as the key to bring him home one day. Some time later, Mickey sorrowfully hands in the Star Shard and the Star Seeker, thinking he has disgraced his master, and prepares to depart. However, Master Yen Sid gives him back the Keyblade, and he happily accepts.

Kingdom Hearts II
Eleven years later in Kingdom Hearts II, Yen Sid serves as Sora's tutor to what lies ahead of him in his journey. He lives in a large tower in a small world-of-sorts connected to Twilight Town via a Magical Train. He dwells at its top, where he studies the Heartless, the Nobodies and Organization XIII. When Sora, Donald Duck, and Goofy arrive, he tells them of the enemies that they will face in the near future (Nobodies, Heartless and the Organization). He also returns to them their Gummi Ship and the co-ordinates to Hollow Bastion.

It is unknown what happens to Master Yen Sid and the 3 fairies, Flora, Fauna, and Merryweather. The last we see of Master Yen Sid is after the Gummi ship is returned to Sora, Donald, and Goofy, and he vanishes. The last seen of the three fairies is when Maleficent's cloak is brought to the tower and they decide to tell Yen Sid about this. Later on if you visit the tower, it is overtaken by Nobodies (more specifically, Sniper, Dragoon, Berserker, Dancer, Gambler, and Dusk), and neither Yen Sid or the fairies are anywhere to be seen. It is assumed, however, that he escaped to Traverse Town, Disney Castle or Hollow Bastion, though most likely in an inaccessible area in the later two worlds, while the fairies either returned to Aurora's world or followed Master Yen Sid to wherever he escaped.

Kingdom Hearts coded
After discovering that Sora has the power to save all the lost hearts connected to him, Mickey meets with Yen Sid to inform him of the whereabouts of Ventus's heart, leaving only Terra to be found. However, Yen Sid shocks Mickey by revealing that the destruction of Ansem and Xemnas will lead to the return of Xehanort, their original persona. Fearing that Xehanort may not be alone, Yen Sid orders Mickey to bring Sora and Riku to the Mysterious Tower to undertake the Mark of Mastery exam.

Epic Mickey
"The world I had created was ravaged, a wasteland..."

- Yen Sid.

Years ago, Yen Sid created a home for the forgotten and retired aspects of Disney, serving as a benevolent, albeit unseen creator, watching from "on high" and enjoying their antics. But one day, his magic mirror opened into the home of Mickey Mouse. When he entered Yen Sid's workshop after he was resting from that evening's work, Mickey played with the magic paintbrush and created a monster, ruining Yen Sid's creation in the process, now dubbed the Wasteland.

In the end, Mickey returns home and is apparently locked out of Yen Sid's studies. Although it seems to be impossible to return, Yen Sid remembers he is Mickey Mouse and with that personality will eventually find a way to return.

Trivia

 * Yen Sid's name, which is not given in the film itself, was given to him by the animators. It is "Disney" spelled backwards which pays tribute to Walt Disney.
 * Kingdom Hearts II marks the first time Yen Sid's voice has ever been heard.
 * The Disney Animators used Disney's "dirty look" (which was the look that Walt gave his animators when he disapproved of their work) for the sorcerer by lifting his eyebrow.