Deku Butler's Son

The Deku Butler's Son is a character mentioned in The Legend of Zelda: Majora's Mask. He is never officially seen in the game, but many player-made theories have arose surrounding this issue.

Theories
The Masks that cause Link to transform in Majora's Mask all seem to have another character's soul that inhabits the mask. The Goron Mask houses the soul of Darmani, the Zora Mask houses the soul of Mikau, and the Fierce Deity Mask presumably houses the soul of a great god. This leaves the Deku Mask with no real explanation of how it helps Link transform. Some theories, however, help explain this.

When Link first enters Temina he is transformed into his Deku form. Soon after, he stumbles across a twisted tree that resembles a Deku. Tatl mentions that the tree looks sad, but nothing is really ever mentioned on the topic until Link beats the Woodfall Temple. After Link beat Odolwa and saves the Deku Princess, he returns her to Deku Palace. Here he meets the Deku Butler who challenges Link to a race. After the race, the Deku Butler comments that Deku form Link resembles his son who has gone missing.

During the ending credits of the game, the Deku Butler can bee seen crying next to the Deku-like tree seen in the beginning of the game, which may imply he has finally found his long-lost son.

In the Manga, the Deku Princess notes the similarity between Link and the Deku Butler's Son.