|“||In order to defeat evil, one must become evil. In a world with the law of the jungle at work, one must rule with power if they wish to accomplish their goals.||„|
|~ The Supreme King|
The Supreme King is one of the main antagonists of the third arc and season of Yu-Gi-Oh! Duel Monsters GX; Dimension World. He is considered one of the darkest characters in the anime, especially due to the fact that he is the alter-ego of the main protagonist Judai Yuki. Specifically, he serves as the main antagonist starting in episode 136 until his defeat in episode 143.
Rise of the Supreme King
The Supreme King was first mentioned by Birdman, after the latter was defeated by Judai. Amazed by Judai's courage and equity, Birdman begged Judai to defeat the evil that rules his world (the Supreme King) and to become himself the King.
As Judai went deeper into the alternate dimension, he could not control his emotions, especially anger and hatred, which resulted in the awakening of his dormant powers. When Zure Knight of Dark World killed a boy who resembled Jesse Anderson, a glowing aura appeared around Judai and Zure remarked that he is not like the other duelists. When several of Judai's friends were sacrificed during the Duel with Brron, Mad King of Dark World, Judai let his hatred and anger to take control over him which awakened the Supreme King's powers inside himself. Judai used those powers in the duel to get revenge on Brron for the loss of his friends. Although the Duel ended with Judai's victory, his remaining friends were disappointed by his actions and left him alone.
Reign of Terror
After the duel, the spirit of the Supreme King sensed Judai's negative emotions and tempts him to evil with the Super Polymerization card that Brron previously tried to complete. He suggests that to truly defeat evil, Jaden himself must become evil. He successfully convinces Judai, and thus became the dominant personality. While in control, his first action was mobilizing an army to slaughter numerous duelists in order to complete the "Super Fusion" card. He later began to oppress many local villages, coercing their allegiance through strong-arm tactics and sets his eyes on a village that serves as his primary resistance for a trap for the survivors of his attacks.
After slaughtering a village, the Supreme King was challenged by Jim Cook, who was utterly horrified when he saw the dark lord's face. Nevertheless, he dueled the monarch. In the duel, he used the Eye of Orichalcum to see the evil inside Judai and tried to destroy it. But despite the eye's power and reducing the Supreme King's life points to 50, Jim was eventually defeated and slain by the Supreme King.
Fall of the Supreme King
After Jim's death, the Supreme King focused all his power on eliminating the last pockets of resistance and completing Super Polymerization. But Austin O'Brien arrived and challenged the Supreme King. After a fierce duel, the Supreme King finally made the winning move, but at the same time, Austin activated a trap that ended the duel in a draw, and destroyed the Supreme King once and for all. Using the Eye of Orichalcum, Austin and Jim's spirit rescued Judai and brought him back as the dominant personality. Judai would later use his alter-ego's power against Yubel later in the season.
In a stark contrast to the carefree and compassionate Judai Yuki, the Supreme King is cold, collected and ruthless, and is willing to sacrifice as many people as he has to in order to complete Super Fusion. He is also very taciturn; he only talks when necessary or to spite his enemies, and when he talks, he speaks in a slightly condescending tone. His demonically golden eyes (and overall visage) show no emotion other than anger and hatred, though he did give a dark chuckle during his duel with Austin.
As an evil counterpart of Judai Yuki, the Supreme King still retains his old Elemental HERO deck, only now he utilizes a magic card known as Dark Fusion, which allows him to fuse his monsters into Evil HEROs, which are twisted versions of of the regular fusion monsters he used before.