Led by the alien-influenced Sartorius, the Society of Light's legion of followers dedicate themselves to worshipping the Light of Destruction, and serve as the main antagonists of the series' second season, intent on cleansing the Earth of its deficiencies.
The Society of Light's members' character designs were overseen by Kenichi Hara. An example of one of these concepts can be seen in Sartorius, who wears the standard Obelisk Blue uniform with a raised and buckled collar and matching cut-offs for his arms and legs. A deck box is strapped to his right leg, presumably to house his regular tarot deck. His blue hair is sectioned in two layers, the layer closest to his face a lighter shade of blue than the one behind it, which generally flows as a single unit. Directly above his nose is another section of hair, colored greyish white, and he also wears earrings and a pair of ornaments on either side of his forehead. He carries an Academy-issued Duel Disk on his left hand despite his initial preference of dueling on a table.
Another example can be seen in Sarina, who wears the ceremonial red and white clothes of a miko with sandals. Her dark hair is elaborately arranged in a flowing ponytail behind her, with the bangs closest to her face positioned on the outermost edges of her head, and she also wears round earrings. She carries an Academy-issued Duel Disk on her left hand.
In the timeline of the Yu-Gi-Oh! GX anime, in the dark recesses of space several hundreds of millions of years ago, a white hole released the dark matter of a black hole, as well as a great energy known as the "Light of Destruction", which bombarded the Earth throughout the course of history, propagating wars, disasters, crimes, and dictatorships. The "Ultimate Destiny Card" created by Aster Phoenix's father was corrupted by such energy; having infectious properties that rival the powers of the Egyptian God Cards and Sacred Beast Cards, the card causes both Sartorius and Pro League king, The D, to develop split personalities, with the former founding the Society of Light.
On the surface the goal of Sartorius and his organization appears to be world domination starting with Duel Academy by expanding their syndicate, but Sartorius evidently wishes to put his stalled fate back into motion through the powers of Aster and Jaden Yuki. In the English version, his goal solely lies in enslaving humanity, while in the Japanese version, he aims to put an end to the "age of darkness" by destroying the planet to restore balance to its imperfect state, and create the world (or on a greater scale, the universe) anew.
Members are brainwashed into the Society's fold by losing to Sartorius or one of his representatives in a Duel, using Sartorius' own mystical powers of fate-prediction and his talent for pushing an opponent's buttons to make them lose faith in their own lives and convince them that joining the Society is a much preferable alternative. Duelists reined into the Society in this manner are usually very devoted to its goals, and have a deep obsession with the color white. Only those with incredibly strong wills or those under the influence of outside forces can escape the Society's hold, and at its basic level, Sartorius' mind control is not necessarily absolute; with some duelists, aspects of their old personalities can shine through on occasion, though this can be rectified should Sartorius exercise more strength in using his powers. The signature card used by the highest ranking members is White Veil, which represents their belief in "light of truth".
Shortly after the second year begins, Chazz Princeton is defeated by Sartorius and coerced into joining the organization. From then on, he serves as means of converting the remaining top Obelisk Blue students (and eventually, the top Ra Yellow students) to their cause. In the process, both Alexis Rhodes and Bastion Misawa are also recruited.
Under Sartorius' request, Chancellor Sheppard invites Prince Ojin of the kingdom of Misgarth (Misralz) to participate in the GX tournament. By defeating him in a Duel, Sartorius acquires the control switch to the country's mind control satellite, along with the two keys for its activation (in the Japanese version, it is instead the most destructive laser satellite in the world, known as Sora (ソーラ Sōra?). To prevent his evil side from instigating his plans, Sartorius eventually approaches Jaden and Aster, giving them the keys. In response, his evil personality assigns more dueling assassins to win the keys back, but is unsuccessful.
Aster then breaks into Obelisk Blue looking for Sartorius, and finds him waiting in the Society of Light's private duel field. Intending to keep his promise of saving Sartorius from his destiny of becoming a destroyer, Aster considers relinquishing his key to the satellite, but is persuaded by Jaden to do otherwise. Recognizing the present Sartorius as an impostor posing as his friend, he wagers the key in a Duel, but is quickly overwhelmed by the Light of Destruction.
Following Aster's defeat, Jaden takes his place to determine the fate of the world by dueling Sartorius. While the battle is taking place, Chazz successfully reverts most of the Society of Light's members back to their former selves with the assistance of a group of Obelisk Blue students, thereby releasing Duel Academy from the Society's grip. Having obtained both keys due to a blunder on Jaden's part, Sartorius takes complete control of Ojin and orders him to the engage the mind control satellite. Sarina hacks into and disables the satellite's programming, allowing both Elemental Hero Neos and Tyranno Hassleberry to destroy it. Shortly thereafter, Jaden defeats Sartorius, and the Light of Destruction is sealed away.
Former Obelisk Blue students
Lorenzo, known as Ryusei Gin (銀流星 Gin Ryūsei?) in the original Japanese language version, is the champion of the "Shooting Game" arcade game. His name in the original version means "silver meteor" when translated in Japanese order. In the English version, Lorenzo is voiced by Anthony Salerno speaking with the accent of a New York mafia member, while Kazuhiro Shindou takes the role in the Japanese version.
Lorenzo is employed by Alexis and Chazz to duel Jaden. Although he is defeated, he comes to understand his opponent's definition of a fun duel, but is punished by Sartorius for his failure. Leaving his hair stark white, Sartorius takes complete control of him and his future.
Lorenzo plays a B. E. S. (Giant Battleship (巨大戦艦 Kyodaisenkan?) in the original Japanese language version) deck. With the effect of Boss Rush, Lorenzo is able to continuously summon B.E.S. monsters as they are destroyed, causing extra damage with Cyber Summon Blaster. The flaw of this strategy, however, is that he is no longer able to summon in any other manner as long as Boss Rush remains in play.
The concept of Lorenzo's cards is derived from the Konami video game series, Gradius. The "Core" monsters are all based on signature Bosses from the games, and the term Boss rush is derived from a gameplay mode commonly found in the series.
Princess Rose (プリンセス・ローズ Purinsesu Rōzu?) is a representative selected by Sartorius to duel Jaden in his place. In the English version, Rose is voiced by Veronica Taylor speaking with a Valley girl accent, while Hiroko Kasahara takes the role in the Japanese version.
Rose claims to have the ability to see Duel Monster spirits (manifested as three "princes" named Jeffrey, Roosevelt and Percival in the English version), but others do not believe her. Jaden, however, notices the spirit of a frog prince watching over her following their Duel.
Rose plays a Frog deck. Through the effects of her trump card Des Frog, as well as T.A.D.P.O.L.E., Rose is able to summon three copies of the former relatively quickly. With her assault team in play, she is able to neutralize all threats and constantly strengthen her monsters with various other cards.
Bob "Game Show" Banter, known as Tsugio Kanda (神田次男 Kanda Tsugio?) in the original Japanese language version, is the Quiz King who has feelings for Alexis. His name in the English version is a pun on the name of Bob Barker. In the English version, Bob is voiced by Matthew Charles referencing numerous existing game shows including The Price is Right, Whammy!, and Who Wants to Be a Millionaire?, while Ryo Kubota takes the role in the Japanese version.
Saddened by the fact that Alexis considers him uninteresting (in the Japanese version, she instead never remembers his name), Bob duels Jaden in hopes of impressing her.
Bob plays a Game Show (Quiz) deck, which sets up the Duel as a game show, with Bob as the host. The majority of his monsters possess abilities that activate when they are flipped face-up, causing damage to opponent if he is unable to answer a posed question correctly, or inflicting damage to himself if he does answer correctly. Once his Quiz Panels are depleted, the summoning of Quizzer Panel 9 allows Bob to return all of them to his deck for another round.
Howard X Miller, also known in the English version and solely in the original Japanese language version as X (エックス Ekkusu?), is Sartorius' lawyer. His name is meant to be a pun in English, as "mill" (a term borrowed from Magic: The Gathering) denotes a direct disruption of a player's deck. In the English version, X is voiced by Ted Lewis, while Yoshitada Otsuka takes the role in the Japanese version.
As a child, X dreamed of becoming a pastry chef, but instead grew up to become an attorney. In the Japanese version, he is instead a Pro League duelist associated with the Society of Light whose ranking is greater than Aster's. He successfully reduced the cards in Jaden's deck to zero, but lost when Jaden was unable to draw due to the effect of the Neo-Spacian Glow Moss he had summoned on X's field, causing him to discard his deck.
X plays a Deck Destruction deck. His strategy relies primarily on Monster Register, a card that, under normal circumstances would effectively demolish the decks of both players. X, however, cleverly protects himself with the ability of Trap Sluzer, while rendering himself almost untouchable with a wide array of Spells and Traps.
Prince Ojin I (オージーン王子 Ōjīn Ōji?) is a professional duelist and celebrity from Misgarth. His name is meant to be a pun, as "ōjin" is the Japanese word for "royal person". In the English version, Ojin is voiced by Darren Dunstan, while Hisayoshi Suganuma takes the role in the Japanese version.
Ojin dueled against Sartorius in the GX tournament. He gloated that he would defeat Sartorius with one attack, but was himself defeated before Sartorius' first turn even came. Upon his defeat, he fell under Sartorius' influence and provided him with the control switch to his mind control satellite. He returns later in the tournament to retrieve one of the switch's keys given to Jaden by Sartorius' good personality, but fails despite aid from the Dark Light. While Jaden and Sartorius face one another in their final Duel, Ojin falls under Sartorius' control once again, and is successful in arming the satellite.
Ojin plays a Satellite deck. His strategic preference involves devoting all his resources to performing a "One Turn Kill" with Satellite Cannon. In the case that this manoeuvre fails, he is also able to fuse three copies of said monster together to summon Satellite Laser Balsam by activating Debris Station for a final wave of destruction.
Dr. Eisenstein, known as Dr. Albert Zweinstein (アルバート・ツバインスタイン博士 Arubāto Tsubainshutain Hakase?) in the original Japanese language version, is a nine-time Nobeli Award-winning German medical doctor with an IQ of 173 specializing in duel physics. His name is a pun on the name of Albert Einstein. In the Japanese version, Zweinstein is voiced by Takeshi Aono.
Eisenstein arrives at Duel Academy under Prince Ojin's request, and is sent by Sartorius to eliminate Jaden and retrieve his key to the mind control satellite, though his underestimation of the young duelist's tactics results in his failure. Bastion idolizes him for his unified theory of the world.
He returns during the third year to communicate with those trapped in the other world, informing them that the key to their escape is to send the Rainbow Dragon card through a wormhole to link both dimensions.
Eisenstein plays a Relativity deck. Being a duel physicist, Eisenstein has researched extensively the interactions between Monster, Spell, and Trap Cards, coming to the conclusion that science overtakes any sort of "luck". As such, his deck exploits statistics and probability, yet in doing so, ignores alternative methods of achieving identical results, as with Jaden's use of Contact Fusion. References to Einstein's interests are made throughout his deck, including mentions of Pierre-Simon Laplace and Schrödinger's cat.
Sarina and the Light Brigade
During the Duel Academy field trip to Domino City, Sartorius enlists the help of his sister and her Light Brigade duelists in luring Jaden and Aster into KaibaLand's virtual world after being granted access to the system by Seto Kaiba. He was concerned with changing the progression of his fate, and wanted Sarina to determine which of the two duelists would be better suited to putting his Wheel of Fate (a metaphor for both Sartorius' destiny and the weapon of mass destruction he would later obtain) into motion.
Sarina, known as Mizuchi Saiou (斎王美寿知 Saiō Mizuchi?) in the original Japanese language version, is Sartorius' younger sister. In the English version, Sarina is voiced by Bella Hudson, while Tomo Sakurai takes the role in the Japanese version.
A miko, Sarina granted her assassins special abilities with her own powers, and erected a barrier around Domino City that prevented Duel Monster spirits from leaving the boundary while Frost and Thunder dueled Tyranno and Syrus. After disposing of her subordinates, she challenged Aster and Jaden to a Tag Duel in KaibaLand's virtual system, but was ultimately defeated. Sarina then revealed that she wished to save her brother from the influence of an evil aura housed in a Hero card that was shown to him when they were younger. In a final act of gratitude, she helped those trapped within the virtual world to escape, but was left behind in the collapsing program, digitizing herself to act as her brother's "guardian". While no mention of it is made in the English adaptation, the Japanese version further includes a promise by Sugoroku Mutou to speak with Seto Kaiba in hopes of restoring her consciousness. Sarina returns near the end of the second year, contributing to the mind control satellite's end. She is flown in to Duel Academy via helicopter by Kaiba's associates, and reunited with her brother.
Sarina plays a Mirror deck. Each of her Silver Spirit (Shikigami (式神?) in the original Japanese language version) monsters, is either sent to the Graveyard to activate Mirror Bind, or to use as fodder for Full Moon Mirror. Once a collection of ten counters has collected on the latter, she is able to play Infinite Fiend Mirror to summon nine copies of her powerful Dark Creator (based on an illustration by Toshiki Nakayama (中山俊希 Nakayama Toshiki?) submitted for a card illustration contest held earlier during the series) to the field. The concept of Sarina's cards is derived from onmyōdō, and she herself takes on the role of an onmyōji during episodes in which she makes appearances.
In Italian version she's called Sabrina.
The Light Brigade
- Thunder, known as Ikazuchimaru (雷丸?) in the original Japanese language version (voiced by Jamie McGonnigal / Takanori Oyama): The "Ikazuchi" portion of the his name in the Japanese version is derived from the word "ikazuchi" (雷), meaning "lightning".
- Frost, known as Kourimaru (氷丸 Kōrimaru?) in the original Japanese language version (voiced by Hidenobu Kiuchi): The "Kouri" portion of his name in the Japanese version is derived from the word "kōri" (氷), meaning "ice," and he sports a Hispanic accent in the English version.
- Blaze, known as Honoumaru (火丸 Honōmaru?) in the original Japanese language version (voiced by Masaki Ishikawa): The "Honou" portion of his name in the Japanese version is derived from the word "honō" (火), meaning "fire".
- T-Bone, known as Iwamaru (岩丸?) in the original Japanese language version (voiced by Toshiharu Sakurai): The "Iwa" portion of his name in the Japanese version is derived from the word "iwa" (岩), meaning "rock," and he has an Ebonic accent in the English version.
The first duo of the Light Brigade, Thunder and Frost, are Tag Duel partners sent to battle Syrus and Tyranno. Unlike Thunder, Frost valued victory above all else, and was not above eliminating his partner from the Duel.
The second pair, Blaze and T-Bone, were meant to be disposed of early on by Sarina. They escaped Sarina's lair and met up with Jaden, at which time Blaze revealed to him that he and T-Bone had themselves once enrolled at Duel Academy, but left after failing an exam. Although they befriended the boy, their master tracked them down and coerced T-Bone into dueling Jaden.
All four Light Brigade duelists were sealed in mirrors by Sarina when she no longer had any use for them, but they were freed after Jaden and Aster defeated her.
Thunder plays a Thunder deck, supported by Tag Duel-exclusive cards. His tactics are more upfront than his partner's in that he utilizes cards such as Rampage Condenser and Lightning Talisman to inflict damage directly, rather than through battle. Frost, on the other hand, plays an Ice deck with similar cards, but his tactics are less upfront than Thunder's in that he utilizes cards such as Mobius Castle and Mobius Glacier to weaken his opponents' monsters, then destroy them through the attacks of Mobius the Frost Monarch.
T-Bone plays a Rock deck, but the signature cards of his fellow Light Brigade duelists were forcefully placed in his deck by Sarina for his Duel with Jaden. His main strategy consists of the repetitive summoning of copies of his Rock-type monsters through Guidance of Ore. The Monarchs themselves fuel the summoning of T-Bone's greatest monster, Demiurge Ema (based on an illustration by Fumiko Kanai (金井文子 Kanai Fumiko?) submitted for a card illustration contest held earlier during the series), which has the ability to draw strength from Spells and Traps that have become "Homunculus Tokens".