Ganon is an antagonist and an alternate form of Ganondorf. He makes an appearance in many Zelda games.
The Legend of Zelda Edit
Ganon makes his appearance in the original Zelda. He steals the Triforce of Wisdom and Link, a protagonist, must kill Ganon.
Zelda II: The Adventure of Link Edit
Ganon's minions attempt to resurrect Ganon by killing Link and mixing his blood with Ganon's ashes. If Link dies in an alternate ending Ganon would rise and conquer Hyrule.
The Legend of Zelda: A Link to the Past Edit
Ganondorf, the Prince of Thieves, disguises himself as Ganon and attempts to steal the Triforce.
The Legend of Zelda: Link's Awakening Edit
Ganon has no appearence in Link's Awakening. However, the final Nightmare takes on Ganon's form.