The Orichalcos (in Japanese: オリカルコス, "Orikarukosu"), sometimes called the "Oreichalcos" (in Japanese: オリーカルコス, "Oriikarukosu"), is the term that refers to an ancient, mystical but evil energy in the Waking the Dragons story arc of the anime series Yu-Gi-Oh!. It appears in nearly all episodes of the season and is the true main antagonist of the arc.