- "A long time ago on a very peculiar day, my mirror lured someone out of his bed...and opened a doorway to my workshop. I do not know if the mirror was being mischievous...or malicious...perhaps it knew that the curious intruder had a role to play in my...project" -Yen Sid
Yen Sid, (from the Fantasia segment "The Sorcerer's Apprentice") created a pen-and-paper world for Disney's forgotten characters with his magic paintbrush, held in an intricate model on a table, and accessible through a mirror. Mickey Mouse spills Paint Thinner on the pen-and-paper world, thus ravaging the world and creating the Blot.
He is voiced by Corey Burton
Many years ago Yen Sid created a world for all of Disney's forgotten, rejected, and retired creations. He crafted an imaginative world full of different wonders that would appeal to anyone who were to enter it. Yen Sid soon used Paint to put the finishing touches on his world ("I was putting the finishing touches on my latest creation--a world for things that have been forgotten."). At the same time Mickey wandered into his workshop, and watched him finishing his creation. Afterwards, Yen Sid retired to his chambers ("Satisfied with my progress, I put the magic brush down and retired to my chambers"). Ignorant, of what Mickey was about to do to this new world ("Had I known what events would follow, I would have locked away everything; Paint, brush and Thinner"), by the time Yen Sid discovered the ruined world caused by Mickey, who created the Blot (he didn't know about Mickey's identity yet), it was too late... ("I heard the noises and rushed to see what had happened, but I was too late. The world I had created was ravaged, a wasteland... The mysterious intruder was gone. I did not learn his identity. Well, not for a very long time...") According to the graphic novel, the reason why Yen Sid didn't fix Wasteland was because he was waiting for Mickey to return to clean up the mess himself.
As Mickey successfully leaves Wasteland after defeating the Shadow Blot, Yen Sid was already there, literally catching Mickey as he comes back into the world ("The intruder returned to my lab, but not in the way I expected."). Mickey gave him back his brush, and Yen Sid ordered him to return back to his house ("After retrieving my brush, I peered down into the world I had created, and noticed something had changed. The wasteland no longer needed my magic. Thanks to the efforts of my apprentice, it had developed some magic of its own. Magic born of courage, and wise choices. And of course, the luck of a certain cartoon rabbit.") As Mickey returns to his house, Yen Sid happily uses the mirror to give Mickey one last look at Wasteland and see the consequences of his past actions while in there. ("The funny thing about mirrors - our reflections prompt us to reflect... on the struggles we have faced or avoided; how well we manage time; enemies defeated or redeemed; the ways in which we treat others; and perhaps most important, the friendships we nurtured or neglected."). He even allows Mickey one more conversation with Oswald, and even bond with him ("Oswald and Mickey are, in some ways, each a mirror for the other. Brave, resourceful, and good of heart. I hope they become friends. And perhaps more, perhaps... even... brothers...") After the credits, Mickey is shown still talking to Oswald and Ortensia via mirror. The image in the mirror changes to Yen Sid, who seals the mirror to his workshop, and supposedly the Wasteland, in order to ensure that Mickey would not cause any more mischief there ("And I have ensured Mickey will get into no more mischief in my workshop"). Yen Sid then states "Then again, he IS Mickey Mouse." As Mickey, unknown to Yen Sid, discovers that he still has some of the Blot absorbed in him, meaning that he can possibly enter the Wasteland against Yen Sid's will and control the Blot's power, having access to magics even more powerful than those of his mentor himself. This is shown in the second game, Epic Mickey 2: The Power of Two when, after falling through the portal into Dark Beauty Castle, he briefly squishes into a puddle before reforming.
- "Not long ago, a rather brave but mischievous mouse discovered a world I had created for forgotten Toons. The mouse faced many challenges and choices, but in the end he saved Wasteland from total destruction with the help of a new friend - Oswald the Lucky Rabbit. With Oswald by his side, good triumphed over evil and a family was reunited. That was only the beginning. As the forgotten Toons rebuilt their home, trouble lurked just around the corner..." -Yen Sid
Yen Sid appears once again in Epic Mickey 2: The Power of Two. He narrates the opening sequence and the ending sequence.
- "And so Ortensia and Gus headed back to the castle to reach out to the one Toon who could truly help them in their time of need..."
- "Working tirelessly for many days and many nights, Gus constructed a device that would put the fate of Wasteland back into the hands of a certain brave mouse..."
- "The curious intruder once again entered my workshop, with one goal in mind: to find and retrieve my magic brush"
- "Mickey needed to retrieve my sorcerer's hat from its fragile cage, but how to do so?"
- "Suddenly, the cosmos spread before him, a plane of imagination fueled by brush, Paint and Thinner."
- "With the brush in hand, Mickey saw that the very stars were waiting to come alive. They needed only Paint to dance once more..."
- "Finding himself at home, Mickey should have felt safe. Looking at the Brush, he wondered if Thinner could help him find the truth behind his unease."
- "Armed with the magic brush, what would Mickey do? Would he paint the world or thin it to nothingness? The choice was his..."
- "And so the brave mouse and the lucky rabbit prevailed against the machinations of the Mad Doctor, and Wasteland was safe once more." -Yen Sid (Good Ending)
- "Although there were some missteps along the way, the brave mouse and the lucky rabbit saved Wasteland from the machinations of the Mad Doctor." -Yen Sid (Bad Ending)
- "Mickey and Oswald did not know what challenges may lay ahead, but they were comforted by the knowledge that, together, they could conquer anything..." - Yen Sid (either ending)
"Walt Disney's boundless imagination resulted in a creation whose potential even he didn't realize: Yen Sid, the formidable Wizard from Fantasia, who is basically Walt's alter ego. It was Yen Sid who crafted Wasteland as a home for Walt's forgotten creations, serving as a benevolent, albeit unseen creator, watching from "on high" and enjoying their antics.
Of course, he could not have foreseen that history would eventually repeat itself as his former "sorcerer's apprentice", Mickey Mouse, would accidentally have an important role in the destiny of Wasteland..." (Yen Sid's Tales of Wasteland profile)
Yen Sid is a character that makes a small appearance in the Epic Mickey: Tales of Wasteland digicomics. These comics are a prequel to Epic Mickey and take place before the Thinner Disaster. He appears in "There's a Hole in the Sky" where he spills some Thinner on his model of Wasteland and creates a hole in the sky that Oswald tries to use to escape Wasteland. He corrects his mistake with Paint when he discovers this.
- The observant reader will notice that "Yen Sid" is "Disney" spelled backwards, a mirror-reflection, if you will. Also, "Yen Sid" is the nickname of the unnamed sorcerer in the film Fantasia given to him by the studio animation department. Animators of Fantasia have commented that they based his scowl on Walt Disney and his scowl of disappointment, so Yen Sid can be considered an allegory of Walt Disney himself, just like Mickey Mouse—although Walt can "make magic" (like Yen Sid) he can sometimes mess up and make missteps (like Mickey), his most infamous misstep being Black Sunday.
- The part where Mickey Mouse enters through the magic mirror to Yen Sid's workshop is based on the Mickey Mouse short: Thru the Mirror.
- Yen Sid can be regarded as somewhat a forgotten character himself, as he had not appeared in any other Disney media since Fantasia and Fantasia 2000, apart from the Kingdom Hearts series (which were also the his first spoken appearance, introducing Corey Burton as his voice actor) and House Of Mouse.
- Yen Sid is the only character who has a spoken script in the first game. All other characters in it communicated through "bark-talk".