Abidos the Third is a villain from the first season of Yu-Gi-Oh! GX. He is the fifth of the Shadow Riders.
He was voiced by Mamoru Miyano, who later voices D in Zyuden Sentai Kyoryuger, in the Japanese version and Darren Dunstan in the English version.
Abidos the Third is an ancient pharaoh. He has never lost a Duel in his life.
He regained his human body by the powers of his Shadow Charm, the Shadow Headband. He then became one of the Shadow Riders. He and his army of mummies abduct the "Keykeepers" to his flying ship in order to Duel them and take their spirit keys.
While dueling Jaden, he realizes that he had never lost a Duel because he only dueled his underlings. They were simply too scared of him, so they would always let them win, just because he was a pharaoh.
Jaden defeats him quite easily, and Abidos realizes what a real Duel is like. He accepts his loss and gives his Shadow Charm to Jaden. He then leaves for the afterlife. He uses a "Servants of the Pharaoh" Deck, with Monster Cards which greatly resemble his own servants.