Mamu

Mamu is a character from Link's Awakening. He is a frog-like creature who resides in the pond beneath the Signpost Maze with his Frog Choir. Mamu is also the leader and conductor of the Frog Choir.

Biography
In The Legend of Zelda: Link's Awakening, Mamu resides in the pond beneath the Signpost Maze. He teaches Link the third and final song for the Ocarina, the "Frog's Song of Soul" by paying him 300 Rupees. After paying the 300 Rupees fee to listen to his jam, Link will learn the "Frog's Song of Soul". Mamu remarks that the ones who hear the song feel more alive. Mamu cannot be revisited as he and his Frog Choir are away on tour according to the sign outside the pond. His fate is unknown after the Wind Fish awaken, as the dream world disappears as well.

Origins
Mamu is a character who originates in another game, ' ('). He was the main villain in the original game where he is the ruler of a storybook world and he sets the events of the game in motion by kidnapping two children and bringing them to his dream factory. The game was localized outside of Japan as  with Mario characters replacing the original Arabian Nights-inspired characters. The US localization changed his name to and instead, he is the ruler of the dream realm Subcon. In Link's Awakening he retains his original Japanese name, Mamu, in the English localization.

Theory
After being defeated at the hands of the hero Mario, the real king of Subcon and the Subcon fairies had the evil frog king caught, however, BS Super Mario USA's backstory reveals that he fleed to another dream world before returning to Subcon, probably being the Wind Fish's Koholint Island itself. This might supports the fact that Mamu had vanished in Link's Awakening.

There is another theory that Mamu is still an enemy despite how friendly he was in Link's Awakekning, as his conquest on Subcon is not necessarily over. There are still members of his army, the 8-bits, who inhabit Koholint Island. There could be some possibilities that he may still command the 8-bits (probably also the members of the Koopa King's army) while acting like an ally.

There's a possibility that Mamu may have awakened from his endless slumber after the Wind Fish awakened, due to the fact that he can only appear in a dream world by sleeping.

Trivia

 * Don Gero from Majora's Mask could have been inspired by Mamu from Link's Awakening, who was also the leader of a Frog Choir.
 * Despite the artwork contains a much more toad-like and older appearance, his sprites looks much more identical to what he originally looks like in Super Mario Bros. 2, and still contains a crown on the head.