“This could be the room of any small boy, but it just so happens to belong to a boy named Christopher Robin. Like most small boys, Christopher Robin has toy animals to play with and they all live together in a wonderful world of make-believe. But his best friend is a bear called Winnie the Pooh, or Pooh for short. Now Pooh had some very unusual adventures and they all happened right here in the Hundred Acre Wood.”
Mr. Narrator is an unseen entity which serves as the omniscient storyteller for most of the Winnie the Pooh franchise.
Unlike most narrators in television programs, Mr. Narrator is not simply a convenient narrative mode to help the (often very young) viewers understand what's going on; he is also an actual character within the stories and interacts regularly with Pooh and his friends. Although the mysterious Narrator never appears on screen, his calm voice is often heard and his presence is usually, though not always, acknowledged by the other characters.
While most installments of Disney's Winnie the Pooh franchise do include meta-references (i.e. "breaking the fourth wall"), The Book of Pooh is particularly odd in that the major characters occasionally find themselves discussing the story with the narrator at the same time this story is happening. Mr. Narrator rarely interferes, however, and prefers to discuss matters with the audience rather than the protagonists if possible. Perhaps his most memorable story was the eponymous episode "Mr. Narrator" in which he attempts to tell a story about himself.
While Mr. Narrator surely fits in the "third-person omniscient narrator" category, his omniscience is sometimes limited, and no matter how much he deviates from the typical narrator figure, he will reveal the end of a story. Welcome to Pooh Corner is the only time when viewers actually see his face.