Ganon is the major antagonist in the famous Zelda series from Nintendo.
Ganon is the holder of the Triforce of Power. Ganon was once a human, but his greed has consumed him. In his advanced states of greed he generally turns into a man with a pig face. The exact reasons for this is unknown but at a time in the comic books Link held both the Triforce of Power and Triforce of Courage and quickly started to look like Ganon.
Ganon originally appeared in The Legend of Zelda for the NES. Ganon kidnapped Zelda twice in the same game. Ganon was thwarted by Link both times.
In The Adventure of Link, Ganon's cult tried to gain Link's blood to revive Ganon.
In 1989 Nintendo produced The Super Mario Bros. Super Show. The show had a cartoon every day and on the Fridays the cartoon would be a Legend of Zelda episode.
Ganon played a pivotal role in the Legend of Zelda Cartoon. Often during the show Ganon would hatch some scheme to try to steal the two pieces of the Triforce that he did not possess. He had the Triforce of Power, but his greed made him want the Triforce of Courage and Triforce of Wisdom. One of Ganon's greatest plans was to kidnap Zelda and have a doppleganger take her place. The plot along with all the other evil plots of Ganon's were foiled by Link and Zelda's combined efforts.
In The Legend of Zelda: A Link to the Past, a wizard named Agahnim tried to revive Ganon, to bring the world into a perpetual night. Ganon was revived but Link yet again saved the day and received the Triforce.
In The Legend of Zelda: Ocarina of Time, Ganon's back story was revealed. Ganon's real name was shown to be Ganondorf. He turned out to be the only male born to the Gerudo for a hundred years. Being the only male made him the Gerudo prince, and his lust and hunger for the Triforce was unmatched. Link's quest was to save the world by gaining the Triforce himself but because of his young age he was not able to wield the power. Ganondorf then received the power of the Triforce and corrupted the world. In the end Link defeated Ganondorf, only to be confronted by his alternate pig faced form, Ganon.
In the two part series, Legend of Zelda: Oracle of Ages and Legend of Zelda: Oracle of Seasons, Koume and Kotake revive Ganon once both games are completed. Once Link defeats Ganon the true ending takes place.
Ganon hasn't been official announced in the newest Zelda games, but at the same time he has not been denied to be included in the future. In addition his occurrence in the Oracle of Ages and Oracle of Seasons were a surprise.