Merlin

Merlin is a sorcerer that first appeared in Kingdom Hearts. He helps Sora understand magic when the boy appeared in Traverse Town.

Kingdom Hearts
''A great sorcerer living on the outskirts of Traverse Town. Merlin's wisdom and magic powers rank second to none, and he teaches Sora and his friends about magic. He has a mysterious bag that can hold anything, no matter how large.''

Kingdom Hearts II
''A powerful wizard who's currently living in Hollow Bastion. He's letting the Hollow Bastion Restoration Committee use his house as a meeting place.''

''Merlin has wisdom and magical powers that are second to none, and he taught Donald most of what he knows about magic. He also has a mysterious bag that can hold anything, no matter how big it is.''

Kingdom Hearts
Merlin is a wizard who originally lived in Radiant Garden, but is first met by Sora in the abandoned house in Traverse Town. Merlin helps Sora and the others with their magic, and also introduces Sora to 100 Acre Wood.

Kingdom Hearts: Chain Of Memories
Merlin is not mentioned in Chain Of Memories but it is assumed that he is still living in Traverse Town.

Kingdom Hearts II
Merlin lives in Hollow Bastion and remembers that it is named Radiant Garden along with the others. He is a member of the Hollow Bastion Restoration Committee. He owns the 100 Acre Wood book again, and the pages are rescattered after a Heartless attack.

Origin
Merlin first and only appearance outside of Kingdom Hearts was in the 1963 film, The Sword In The Stone. In the film, Merlin teaches the young King Arthur some life lessons and prepares him for a life as the ruler of England. He also has a rivalry with Madam Mim, but this rivalry has yet to manifest in Kingdom Hearts. Merlin also has pet owl named Archimedes, who has not been seen in Kingdom Hearts.