Merlin is a wizard of unspecified origin, who originally lived in a forest cottage. He is a very wise character who believes in the philosophy of "Brain over Brawn". To this end, Merlin values education as opposed to the war-training of the rest of society. Despite his wisdom, he can be absentminded and forgetful, as well as clumsy.
As a wizard, Merlin shows a wide variety of powers, and is widely hailed as being the most powerful wizard in the world. He shows an ability to see into the future, though not exactly. He can enchant both objects and people, and possesses a well-developed ability to shapeshift. He can also travel through time, which has granted him much knowledge about society. He often references his knowledge of the future when speaking to others, leaving them confused.
The Sword in the StoneEdit
Merlin is first seen preparing afternoon tea in his cottage, having predicted that a young boy will soon join them. He admits that the specific identity is unknown. He later meets a pre-teen orphan called Arthur, commonly known as the Wart, after the boy literally drops through the roof. Merlin speaks to the Wart about the value of an education and decides to appoint himself as the Wart's tutor. After Wart explains that he must return to his castle, Merlin decides to accompany him, and displays his magical abilities by shrinking all his possessions so that they fit into a small carpet bag.
They arrive at the castle of the Wart's foster father Sir Ector. Though Sir Ector initially disapproves, Merlin is able to persuade him though a display of magic, which frightens the man into accepting Merlin's offer. Merlin, who is confusedly called "Marvin" by Ector, is provided the "guest room", which is apparently a crumbling, teetering tower.
The next day, Merlin begins the Wart's education, teaching him the principle of brain over brawn by transforming the Wart into a fish. During the adventure Merlin, also in fish form, is trapped in an old helmet, while the Wart is chased by a giant pike. Merlin forgets the magic words to change them both back, but remembers just in time.
Later, Merlin goes to retrieve the Wart for another lesson, but the Wart is being forced to clean as punishment for being late as a result of the previous lesson. Merlin uses his magic to enchant the various kitchen objects into cleaning themselves, and sneaks the Wart out. Merlin transforms himself and the Wart into squirrels, where they live the dangerous life of the creatures. Merlin and the Wart are both pursued as mates by 2 female squirrels. Merlin grows increasingly annoyed and finally transforms into a human out of anger. He then transforms the Wart, much to the sorrow of the young female squirrel who had been chasing the boy.
Back at the castle, Merlin is insulted by Sir Ector, who believes that Merlin's magical enchantment of the kitchen objects is black magic. When the Wart protests in defending Merlin, But Ector angrily piles more demerits on the boy, and finally punishes him by forbidding him from making a future trip to a London tournament as Kay's squire, and replaces the boy with his unseen boy groom Hobbs. After seeing the Wart's sadness, Merlin apologizes, as he knew how much the potential trip to London meant. He then suggests that the Wart use the opportunity to further his studies and that he can still make something from an education.
Merlin begins by talking of various happenings of the future, but the poor boy is so confused that Archimedes decides to take over the Wart's education. Despite Merlin's annoyance, he is later pleased to see the boy learning to write with Archimedes's help. Merlin takes the opportunity to show the Wart a model airplane. The plane fails to fly though, because the propeller becomes caught in Merlin's long beard. The Wart appreciates the demonstration anyway, and confides that he dreams of flying. Merlin decides to turn the Wart into a small bird. The Wart then goes flying with Archimedes.
After being told of the Wart's capture by Madam Mim, Merlin appears. Mim angrily challenges Merlin to a Wizard's Duel, where he turns into a turtle, a rabbit, a walrus, a caterpillar, a goat, a crab and a mouse. Though initially at a disadvantage, Merlin wins by cleverly transforming into a germ.
Later, the Wart happily informs Merlin that he has been reinstated as the squire to Kay. Merlin is angry, as he thought the Wart had put aside war games in favor of learning. When the Wart explains that a position as a squire is best hope, Merlin angrily turns into a rocket and travels to Bermuda. Later, he returns to where he is pleased to find that the Wart is now King Arthur and tells him how famous the boy will become in the future.
In Kingdom HeartsEdit
Kingdom Hearts Birth by SleepEdit
Merlin appears in Radiant Garden before the world is engulfed in darkness. He accidentally drops the book granting access to the 100 Acre Wood, but Terra returns it to him. He also interacts with Aqua and Ventus to do the same when they pass through. Looking inside the book grants the three Keybearers access to the 100 Acre Wood Command Board.
Merlin is sent by King Mickey to Traverse Town, where he sets up in the ramshackle house hidden in a secret underground lake behind a wooden door with a fire symbol, located in the Third District, along with the Fairy Godmother. Sora, Donald and Goofy can meet him as soon as they learn Fire, in order to open the door, but they must talk to him after Cid asks them to deliver the 100 Acre Wood book to the wizard. Merlin appears in a puff of smoke to greet them, and teaches them how to properly use magic. The upper level of the house is empty, but can be used for magical training against enchanted furniture. After Sora delivers the repaired book to Merlin, he explains its special nature, but Sora is magically sucked into the secret world. Merlin will also give the heroes the Spellbinder, Dream Rod, and Dream Shield once they reach certain levels of magical skill.
Kingdom Hearts IIEdit
Merlin now lives in Hollow Bastion which is being rebuilt. He lives in a large cottage which serves as the headquarters for the Hollow Bastion Restoration Committee. Merlin is part of the committee along with Leon, Yuffie, Aerith, and Cid. Upon reuniting with Sora, he grants Sora the Blizzard element. Merlin gives Sora his first Summon charm which unlocks Chicken Little. Merlin also retrieves the 100 Acre Wood book from Traverse Town's Zero District and places it on a shelf in his house. Later, he travels to Disney Castle with Sora, Donald, and Goofy to open up a magical door to the past. Merlin seems to have developed a rivalry with Cid, who prefers technology to magic, while Merlin prefers magic to technology. Their rivalry nearly gets out of hand when Cid calls Merlin an "old loon", and Merlin zaps Hollow Bastion's power computer, but thanks to Sora, Donald and Goofy, the town's systems are saved. Merlin and Cid later recall that Hollow Bastion was formerly called Radiant Garden and decide to rename it to its former name.
Kingdom Hearts 3D: Dream Drop DistanceEdit
Although Merlin doesn't appear in Dream Drop Distance, he is mentioned briefly. Yen Sid mentions to Mickey that Merlin and the three fairies are helping Lea to train in wielding the Keyblade by magically suppressing his training sessions.
On Sora's TeamEdit
Ever since the team formed, he was happy to be a member and train new comers. As a powerful wizard, he has his own magic class.