Yu-Gi-Oh! Duel Monsters GX (遊☆戯☆王デュエルモンスターズGX Yūgiō Dyueru Monsutāzu Jī Ekkusu?, lit. "Game King Duel Monsters GX") is ananime spin-off and sequel of the original Yu-Gi-Oh! Duel Monsters anime. It aired in Japan on TV Tokyo between October 6, 2004 and March 26, 2008, and was succeeded by Yu-Gi-Oh! 5D's. Yu-Gi-Oh! Duel Monsters GX follows the exploits of Judai Yuki (or Jaden Yuki in the American version) and his companions as he attends Duel Academia. It was later dubbed in English by 4Kids Entertainment and a manga spinoff was created by Naoyuki Kageyama each under the name Yu-Gi-Oh! GX (遊☆戯☆王ジーエックス Yūgiō Jī Ekkusu?, lit. "Game King GX"Edit
Ten years after Yu-Gi-Oh! Duel Monsters, Yu-Gi-Oh! Duel Monsters GX follows a young boy named Judai Yuki (Jaden Yuki in the English dub) who, along with his friends, attends Duel Academia (Duel Academy in the English dub), a special institute founded by Seto Kaiba, in the hopes of becoming the next King of Games. Using his Elemental Hero deck and a Winged Kuriboh given to him by Yugi Mutou, Judai faces various challenges against other students, teachers and other mysterious beings.
For the first two years at Duel Academia, the main cast faces major threats including the Seven Stars Asssasins (Shadow Riders in the English dub), who intend to revive the Three Phantom Beasts (Sacred Beasts in the English dub) by creating a strong dueling presence on the island and obtaining the Seven Spirit Keys. They are held by Judai Yuki, Ryo Marufuji, Asuka Tenjouin, Daichi Misawa, Jun Manjoume, Professor Cronos de Midici and Daitokuji-sensei (Zane Truesdale, Alexis Rhodes, Bastion Misawa, Chazz Princeton, Dr. Vellian Crowler and Lyman Banner in the English dub), as well as the Society of Light, which intends to destroy all life with the mind control satellite of Misgarth (they want to enslave humanity in the English dub). During the third year, Duel Academia is transported to another world–a desert plane with three suns and resident Duel Monster spirits–right into the hands of the Martin Empire. Upon returning home, Judai and a select group of his partners dive into the rift left in their escape to recover their missing companion, Johan Anderson (Jesse Anderson in the English dub), and embark through second and third worlds called Dark World. Judai and friends meet up with an underground group that intends to fight the Dark World Order. During the duel that was Judai vs Brron: Mad King of Dark World, Jun, Hassleberry, Asuka, Ojama Green, Ojama Black, and Atticus are killed (in the english dub they are "sent to the stars"). After Judai wins, he feels completely alone, and the spirit of the Supreme King takes over Judai's body. Jim and Austin die trying to bring Judai back to his normal self. Judai overcomes his fear of the dark power that controlled him. During those very dark times, they find themselves face to face with the vindictive Yubel. When Judai realizes the connection between Yubel and his past self, he uses Super Fusion (Super Polymerization in the English dub) to fuse his soul with Yubel's, giving him certain powers and setting his friends free.
In their final adventure, Judai and his friends deal with the mysterious Mr. T or Trueman as he calls himself, a dark agent who copies the identity of his defeated opponents and seemingly wipes out their existence with them, trapping them in a nightmarish realm where they are mentally tortured by their personal failings. When a solar eclipse draws near, Mr. T is revealed to be working for the real mastermind behind the vicious plot around the entire season - the former Seven Stars Assasin, Darkness (Nightshroud in the English dub), using Yusuke Fujiwara as an avatar. Judai and Johan form a tag team to defeat Fujiwara and later Darkness himself in order to save the rest of the humanity from his World. After Judai graduates, he is sent back in time in order to have an opportunity to duel with a younger Yugi Mutou.
Yu-Gi-Oh! Duel Monsters GX is produced by Nihon Ad Systems, Inc., and directed by Hatsuki Tsuji. Scripts are prepared by an alternating lineup of writers–Shin Yoshida, Jun Maekawa, Akemi Omode, Yasuyuki Suzuki–with music arrangements by Yutaka Minobe. Takuya Hiramitsu is in charge of sound direction, supervised by Yūji Mitsuya. Character and monster designs are overseen by Kenichi Hara, while Duel layout is overseen by Masahiro Hikokubo.
The "GX" in the series' title is short for the term "Generation neXt". "GENEX" was conceived as the series' original title, as can be evidenced in early promotional artwork. It also refers to the GX tournament that takes place between episodes 84 and 104.
The program is divided into episodes classified as "turns". The title sequence and closing credits are accompanied by lyrics varying over the course of the series, with the former immediately followed by an individual episode's number and title. Eyecatches begin and end commercial breaks halfway through each episode; in the first season, there were two eyecatches per episode, usually showcasing the opponents and their key monsters for a given episode while in later seasons, a single eyecatch appears with only the duelists. After the credits, a preview of the next episode, narrated most frequently by KENN and Masami Suzuki, is made, followed by a brief "Today's Strongest Card" segment.