Segoy

Segoy is the creator of the islands of Earthsea. Its origins are unknown, nor is it known what sort of being it was. It may be one of the Old Powers of the Earth, or the Earth itself (according to A Description of Earthsea). It is referred as the father of the dragons. Given dragons and humans have a common origin, this may make it the father of humanity as well in some way.
According to The Creation of Éa, the oldest and most sacred epic poem in Earthsea's mytho-historical record, Segoy created the islands and the light itself by speaking them into existence, giving everything its True Name.
It is possible that Segoy is actually Kalessin, a dragon known respectfully as "The Eldest"; or at least that Kalessin is one of several guises of Segoy. Tehanu addresses Kalessin as Segoy at one point while speaking in the Language of the Making, in which all names are true names, and Ged seems to confirm it a moment later when he calls Kalessin “the giver of names.” However, Tehanu also calls the dragon by the name Kalessin at other times, and it would be impossible for Tehanu to name it falsely using the True Speech. It is a riddle how Segoy could have more than one True Name, since wizards believe true names are mutually exclusive. However, there may be a clue in A Description of Earthsea, which cryptically says, “Some think all dragons, or certain dragons, or certain people, are manifestations of Segoy.”