Jaden Yuki
The main protagonist of the series. He is described as an energetic, passionate and optimistic boy who comes to Duel Academy to learn to become the new King of Games. He enjoys seeking out new duel challenges and is known to be quite lucky when it comes to his draws. He is capable of communicating with Duel Spirits, most often conversing with Winged Kuriboh, a card he received from Yugi Muto on the day of his entrance exam. He specializes in using Fusion Monsters, his main deck being the Elemental Heroes deck before later obtaining a set of Neo-Spacian monsters and his key card, Elemental Hero Neos. Following the third season, in which he entered an alternate dimension and confronted the duel spirit, Yubel, he has gained the powers of both The Supreme King, an evil alter-ego he temporarily took on, and Yubel, giving him powerful insight.

Syrus Truesdale
Jaden's roommate at Duel Academy. He often doubts himself, living in the shadow of his older brother Zane,but has shown himself to be a talented duelist, managing to rise in the ranks from Slifer Red to Ra Yellow to Obelisk Blue. He battles using a Vehicroid deck, which in season four becomes a Cyberoid deck that he creates by implementing Zane's Cyber Dark Dragon deck.

Chumley Huffington
Chumley was forced to retake his freshman year after he failed his first time around. His best friends, Jaden Yuki and Syrus Truesdale, come to Duel Academy, and encourage Chumley to gain more confidence in himself. He watches Jaden duel Chazz and becomes thrilled when he won and later joins him and Syrus to intestate the abandoned dorm. Throughout the series, Chumley participates in only two Duels: the first against his father, Mr. Huffington, and the second against Dr. Crowler. His father believed that his son's efforts at Duel Academy were wasted and that he would be better off leaving. To put an end to the conflict, Chumley struggled valiantly against his father's special tactics, but ultimately lost. Despite this, he allowed his son to continue his studies, as he saw that Chumley had actually learned something, and that his friends would always support him!

Bastion Misawa
A duelist associated with Ra Yellow and is regarded as a dueling genius, having the top grades of his freshman applicant class. His strength is in studying and preparing for different situations, relying on rational methods. He possesses six carefully calculated decks for each Monster attribute; he claims that a single carelessly added card can throw off their balance. At the end of season three, he stays behind in an alternate dimension to help out its inhabitants. In both the manga and anime, Bastion is shown to research those he seeks to duel to devise strategies to use against them; in both cases, he found a way to seal Fusion to keep Jaden from Fusion Summoning stronger Elemental Heroes. In the manga, Bastion is shown to use a Yokai deck.

Chazz Princeton
A freshman duelist who ranks in the Obelisk Blue. He is elitist, thinking that low-scoring duelists such as Jaden should be kicked out. He thus becomes one of Jaden's rivals throughout the series, though he eventually gains a mutual respect for Jaden later on. It is revealed early in the first season of the series that his elitism stems from his older brothers who urge him to become a great duelist in order to have their family reign over the dueling world, as his brothers rule over the political and financial worlds. After becoming estranged with his brothers, Chazz decides to pursue a career in dueling, without their help. It is revealed that Chazz has a soft side in the second season. When Alexis's brother arrives to take his sister to make a band, they have a duel. During the duel, Chazz cheers on Alexis. He also has an awkward crush on her. He initially uses a power based deck, focusing on powerful monsters such as the Armed Dragons. Later on, he becomes able to see duel spirits and starts using the Ojama Trio, a trio of brothers with zero attack points but several uses. Following his time at Duel Academy, Chazz Princeton later went on to found Princeton University.

Alexis Rhodes
A beautiful and talented duelist who is regarded as the queen of the Obelisk Blue. She is not elitist like many of the other Blue members, and quickly takes interest in Jaden.Later, it is also revealed that she loves Jaden. She duels using a Cyber Girl deck. Jaden accepted a duel with another player, and whomever won was to be engaged to Alexis, Jaden won but in the end had no idea what fiancee meant so Alexis responded " It means friends. At least for now, big guy." She also knows that Chazz has a crush on her. Alexis, along with Zane Truesdale and initially Chazz Princeton, is one of the top students at Duel Academy. She does not follow the crowd nor does she regard herself as better than other people like some students in the dormitory, but has a stern pride as an Obelisk Blue duelist. Alexis mourns for her long-lost older brother, Atticus Rhodes. With the help of Zane, the top duelist at Duel Academia, she constantly searches for clues surrounding his disappearance, until it is revealed that he joined the Shadow Riders, under the control of Nightshroud. Later in the series, Chazz comes out about his infatuation with Alexis after Jaden defeats the final Shadow Rider. At the start of the second year, Alexis moves into a spare room in the Slifer Red dormitory to escape Dr. Crowler, who was pestering her to begin a career with her brother as duelists that sings pop songs during duels. Following Chazz's entrance into the Society of Light, Alexis duels with him to keep him from taking over Obelisk Blue completely. She fails, however, and meets the same fate as her fellow elites.

Zane Truesdale
A third-year Obelisk Blue student and the king of Duel Academy, nicknamed "Kaiser" in the Japanese version. He is the older brother of Syrus. He serves as one of Jaden's friendly rivals in the first season. However, when he loses a duel against Aster Phoenix in Season 2, he starts participating in underground duels and takes on a more aggressive personality, earning him the name "Hell Kaiser" in the Japanese version. The underground duels in which he battled using shock collars caused his heart to become weak. In Season 3 he teams up with Aster to help Jaden and his friends look for Jesse, while searching for a worthy opponent to give him one final duel before he dies. He uses a Cyber Dragon deck which he later passes on to Syrus. In Season 2, he starts using a Cyberdark deck to fit his new aggressive nature.

Blair Flannigan
First appearing in "The Maiden in Love", Blair Flannigan is a young girl who enroll into Duel Academy disguised as a boy in hopes of getting close to Zane Truesdale, her crush. After being caught by Jaden while sneaking into Zane's dorm room, he defeats her in a duel and confesses her love to Zane but is politely rejected due to her being in fifth grade. Afterwards, she leaves Duel Academy and turns her affections to Jaden, promising to return to Duel Academy and enroll when she is older. In "The Hands of Justice (Part 2)", she returns to Duel Academy in the midst of the GX Tournament to duel Zane but is again rejected and is given his GX medal. Dueling Chazz in the final match, she is defeated but is accepted into Duel Academy after proving her worth as a duelist. Blair uses a deck of girls to sway her opponent's male monsters in the first season and later uses a deck of "Egg" monsters.

Tyranno Hasselberry
A duelist who enrolls in Jaden's school during the second season and is grouped with Ra Yellow. He has a muscular physique and plays a Dinosaur deck. When he was younger, he had an accident where scientists implanted a dinosaur bone in his leg. Hassleberry uses a Dinosaur Evolution deck.

Adrian Gecko
A new student hailing from East Academy and enters Duel Academy in the third year. He carries a digi-recorder and is often seen taking notes on it. For most of his life, he has always put the needs of others ahead of himself. He was adopted by the Gecko family and was supposed to be the future heir until his brother was born. Since then, he has devoted his time to help him despite the less attention he's gotten and being looked down upon. Adrian gets sent to another dimension by Yubel and tries to become king. He first duels using a cloud type deck then obtains the full power of Exodia by sacrificing his childhood friend Echo and defeats Aster Phoenix in season 3. After losing a duel to Jesse possessed by Yubel, he gets sent to the stars and does not come back. Only after the duel when Echo disappears completely does he mourn her loss. He and Echo are the only ones that permanently died in the other dimension.

Chazz Princeton
A talented professional duelist who enters Duel Academy as a freshman during the second season. When he was young, his father was mysteriously killed and he was taken in by Sartorius, being used as a pawn in his plans. Similar to Jaden's Elemental Hero deck, Aster uses a Destiny Hero deck, symbolizing his desire for vengeance.

Atticus Rhodes
His given name means "blizzard", from which he derives his self-appointed title, "Blizzard Prince" in the original version of the series. Atticus Rhodes is the missing brother of Alexis and his disappearance is a driving force in his sister's determination during the first season of the series.

Axel Brodie
Initially Professor Viper's right-hand man introduced during the third season. He is described as being tough and having a "no-nonsense style and military upbringing". This is also referenced by his Duel Disk, which is in the shape of a gun that can shoot cards when needed. Axel uses the Volcanic deck. He eventually joins Jaden as one of his allies.

Fonda Fotaine
Fonda Fontaine is the supervisor of the female Obelisk Blue dormitory, as well as the school's head medic and gym instructor. During the third year, while trying to protect an injured Blair Flanagan, she is transformed into one of Marcel's Duel Ghouls and duels with Jaden, though she recovers after Duel Academy is returned to its proper place from an alternate dimension. Ms. Fontaine plays an Anti-Cure deck.

Jasmine
One of Alexis's boy crazy roommates in the female Obelisk Blue dormitory. She has almost no talent for dueling and would much rather gossip, shop, or fantasize about Alexis's brother Atticus.

Jean-Louis Bonaparte
Vice-Chancellor of Duel Academy beginning with the second season, Bonaparte is a stout man hailing from Paris, France who originally attempted to demolish the Slifer Red dormitory at every opportunity, but was repelled by Dr. Crowler. He later dueled alongside Crowler against Maximillion Pegasus for a job at Industrial Illusions, after they falsely believed themselves to be fired by Chancellor Sheppard. Following Duel Academy's arrival in an alternate dimension, he encourages the students to save his son Marcel from the Duel Spirit Yubel. Previously married, Bonaparte's son is in the custody of his ex-wife. After Marcel is rescued, Bonaparte apologizes for neglecting him and leaving his wife for his career, and the two return to France at the end of the season. Bonaparte plays a Toy Army deck. His character is based on Napoleon I.

Jessie Anderson
A North Academy duelist described as loyal, friendly, and fun-loving. He and Jaden become friends and allies for the series. He uses a Crystal Beast deck and searches for the Rainbow Dragon card, which he eventually acquires in season 3. He activates the card to take the Academy and the rest of the students back to their world, leaving him behind, where he is possessed by Yubel, but rescued by Jaden. In season 4, Jesse helps Jaden defeat Mr. T to save everyone and the world. It is shown that Jesse was at the graduation party at the end.

Jim Cook
Introduced in the third season as an Australian duelist originally from South Academy, but now enrolled with Duel Academy. He is described as tough, cunning, but having a carefree attitude. He has a pet crocodile named Shirley, who he saved when he was younger. He wears bandages over his right eye, which is revealed to house an Eye of Oricalcum that allows him to see a person's true nature. He uses his power to try to free Jaden from the Supreme King but fails and winds up getting sent to the stars and is later rescued. He duels using a fossil deck and his duel disk resembles a boomerang.

Lyman Banner
The head of Slifer Red in Duel Academy who, often speaks with a 'nyaa' at the end of his sentences. He is later revealed to be an alchemist who used a homunculus body to prolong his life while he joined the Shadow Riders in order to seek out the Three Sacred Beasts. When he is defeated by Jaden, his body dissolves into dust, but his spirit remains with Jaden, offering him advice whenever possible.

Mindy
One of Alexis's boy crazy roommates in the female Obelisk Blue dormitory. She has almost no talent for dueling and would much rather gossip, shop, or fantasize about Alexis's brother Atticus.

Sartorius
A fortune-teller with dual personalities under the influence of The Light Of Destruction. Sartorius serves as the main antagonist of the second season, poised to remake the world in the image most befitting the extraterrestrial radiance within him. Sartorius plays an Arcana Force deck.

Lorenzo Plata
Lorenzo is the champion of the "Shooting Game" arcade game. His name means "silver meteor" when translated in Japanese order. 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. deck.

Rose
Princess Rose is a representative selected by Sartorius to duel Jaden in his place. Rose claims to have the ability to see Duel Monster spirits, 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.

Bob Banter
Bob Banter is the Game Show King who has feelings for Alexis. Saddened by the fact that Alexis never remembers his name, Bob duels Jaden in hopes of impressing her. Bob plays a Quiz deck.

Howard X. Miller
X is a Pro League duelist for the Society of Light. 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. X is a Pro League duelist associated with the Society of Light whose ranking is greater than Aster's. In the English version, X of dreamt becoming a pastry chef as a child, but instead grew up to become an attorney. 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.

Prince Ojin
Prince Ojin 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". Ojin dueled against Sartorius in the GX tournament. He gloated that he would defeat Sartorius with one attack, but was himself defeated before Sartorius's first turn even came. Upon his defeat, he fell under Sartorius's 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's 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's control once again, and is successful in arming the satellite. Ojin plays a Satellite deck.

Dr. Eisenstein
Dr. Eisenstein is a nine-time Nobel Award-winning German physicist, with an IQ of 173, specialized in duel physics. His name is a pun on the name of Albert Einstein. 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.

Sarina Saiou
Sarina is Sartorius's younger sister. A Priestess, 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 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 Solomon Moto 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.

Dorothy
Dorothy is a school staff member who works in Duel Academia's card shop, Dorothy actually has very little knowledge of the rules of a Duel. In the English version, she is "Miss Duel Academy." There is an ongoing romance between her and Chancellor Sheppard. Dorothy is not a good character to team up with - she is ineffective as a partner, using extremely weak Decks specifically made to be a burden no matter what kind of Deck the player uses by wasting their cards to summon weak monsters, with the player being unable to remove or reduce the possibilities of it happening by editing her Deck due to every card in her Partner Decks being marked as favorites. This extends to the minigames as well - during the Dodgeball minigame, for example, Dorothy tosses only cream pies and does not move from her position. Should the player get knocked out, she will start playing normally, although she will still remain in her position.

Kagemaru
Kagemaru is the leader of the Shadow Riders and the main antagonist of the series' first season as well as the former superintendent of Duel Academy. Kagemaru hoped to attain eternal youth by sacrificing Duel Monster spirits to the Sacred Beasts. During his duel with Jaden, his youth was returned. After being defeated, however, he returned to his aged state. He then asked forgiveness and promised to renounce his former ways, carried off to the hospital by helicopter. Kagemaru plays a Sacred Beast deck.

Nightshroud
Nightshroud is the 1st of the Shadow Riders. But in reality, Nightshroud is an entity of unknown origin tied to the darkness itself and the final antagonist in the series. He entered the body of Atticus Rhodes and took control. Being the owner of the other half of the Shadow Charm pendant in Jaden's possession, Nightshroud sets a Shadow Game for both of them where the loser has his soul sealed in a card. When defeated, Nightshrouds' soul is sealed away, and Atticus is freed. During the Tournament, Atticus uses Nightshrouds' deck in hopes of convincing his friend, Zane Truesdale, that the dark path taken by a duelist is a terrible course. As a result, Nightshrouds' influence is once again able to take control of Atticus, only to be banished following his defeat. In the fourth season, Atticus again uses Nightshrouds' deck to duel Jaden, revealing he still has nightmares about his alter-ego. During the duel, Atticus remembers that one of the missing students at the academy, Yusuke Fujiwara, was the original host of Nightshroud and before he vanished, he made Atticus into a temporary host for Nightshroud to inhabit. But Nightshroud eventually returns in the body of Fujiwara, and though he loses to Atticus in a one-on-one duel, he cheats reversing time and preventing Atticus from activating Inferno Fire Blast. But, after losing to Jaden when he and Jesse double teamed Yusuke, Nightshroud left his vessel and duels Jaden in a match with the world at stake. Jaden reverses all of Nightshrouds' evil doings and finally destroys him. Though beaten, Nightshroud boasts that as long as there is darkness in humans, he would return, but Jaden counters by claiming that as long as there are bonds between humans, Nightshroud has been sealed. In his final duel, Nightshroud is portrayed as a megalomaniac or simply insane, once he claims he is God and the Savior. Nightshroud, while possessing Atticus, plays a Red-Eyes Darkness Dragon deck. Within Yusuke's body, Nightshroud uses a Clear deck. Once without a host, Nightshroud uses his personal Darkness deck.

Camula
Camula is the 2nd of the Shadow Riders. Her name is derived from the title of Joseph Sheridan le Fanu's novel, Carmilla. A vampire, Camula is very serious when it comes to dueling, as she hopes to revive her race from its destruction by the people of Medieval Times. She had been asleep within her coffin until Kagemaru uncovered it and invited her to join the Shadow Riders. She captures the souls of her opponents following their losses within dolls to fuel her cause, and uses the Shadow Charm strangler around her neck to bet the souls of others in conjunction with the Shadow Game-exclusive Illusion Gate to ensure victory. She manages to obtain the keys of Dr. Crowler and Zane, but during her duel with Jaden, her Shadow Charm's power is negated by the completed item that Jaden possesses. Out of self-confidence, Camula places her own soul on the line, and it is dragged into the gate after she loses, leaving her body empty and turning it to dust. Camula plays a Vampire deck.

Tania
Amazoness Tania is the 3rd of the Shadow Riders. A white tiger that assumes human form with her Shadow Charm gauntlet to find a worthy duelist to be her husband, Tania travels with another tiger named Bass, who resembles the Amazoness Tiger. She falls in love with Bastion Misawa, and after some sweet talking and showing off her amazing dueling skills, defeats him and makes him her bridegroom for a short time until she grows tired of him. Tania then fights Jaden in a soul match with the effect of Amazoness Arena, and eventually resumes her true form and runs off. She appears before Jaden and his group during the third year as her human self, having been sucked into the second alternate dimension they visit since their last meeting. She serves as their guide through the first town they encounter, and stays behind with Bastion after Jaden liberates it. Tania's Amazoness cards, based on the Amazons of Greek mythology, are divided into two decks: Courage and Knowledge. She uses the Knowledge deck against Bastion, and the Courage deck against Jaden.

Abidos
Abidos the Third is the 5th of the Shadow Riders. His name is derived from the name of the ancient Egyptian city, Abydos. An ancient pharaoh who never lost a single duel, Abidos regained physical form through the powers of the Shadow Charm headband he wears. With an army of mummies, Abidos gathers Jaden and company on his celestial yacht for a duel. During the duel with Jaden, Abidos realizes that the only reason he kept winning was because his opponents always lost on purpose, simply because he was pharaoh. Jaden, however, manages to give Abidos a real duel in which the opponent actually tries to win. Satisfied with his defeat, Abidos departs for the afterlife, giving Jaden his Shadow Charm, the latter making a promise to meet him again in one-hundred years time, presuming that Jaden will be dead within that time. Abidos plays a Servants of the Pharaoh deck.

Titan
Titan is the 6th of the Shadow Riders. A hitman originally hired by Crowler to deal with Jaden, Titan captured Alexis Rhodes to force Jaden into a duel for her life. Despite his reputation of possessing the power of a Millennium Item, the "Millennium Item" turned out to be a fake Millennium Puzzle, and Titan used various tricks to mimic a Shadow Game. He became the victim of a real Shadow Game, however, but was saved by Kagemaru, wearing a Shadow Charm mask to bind him to the real world. Taking advantage of Alexis's desire to restore her brother's memories, Titan challenges her in the abandoned dorm where they first met. He is ultimately pulled back into the pits of darkness when he is defeated. Titan plays an Archfiend deck.

Amnael
Amnael is the seventh and final member of the Shadow Riders. A homunculus inhabited by Banner's soul. Unable to find Banner's cat Pharaoh, Alexis Rhodes, Chazz Princeton, Jaden Yuki and the others start looking for him. While looking, Amnael challenges and defeats both Chazz and Alexis in a duel, who then get sucked into Amnael's book as a result. Jaden gets lead to the abandoned dorm where he defeated Titan. There he finds a mummified body that resembles Banner, and Amnael who later reveals himself to be the spirit of Banner. Amnael and Jaden duel, which results in Jaden's victory. After giving Jaden his Emerald Tablet which previously held his Shadow Charm, Banner is reduced to dust along with his original mummified body. His spirit, however, lives on in the stomach of Pharaoh. His appearance is seen when the cat is clueless causing its body to retrieve Banner's spirit for a short amount of time.

Sheppard
The chancellor of Duel Academy, Sheppard watches over the students in his school, but is often directly responsible (though not always fully aware of it) for many of the incidents that befall Jaden and co. In the second season, Sheppard left Duel Academy under the care of Crowler, and was sought by Zane, who wanted to obtain the Underworld deck that lay dormant within his dojo. He eventually resumed his position in time for the GX tournament, part of a plot devised by both himself and Pegasus to lure out the person possessing the famed Ultimate Destiny Card. Sheppard plays a Cyber-Style deck.

Vellain Crowler
A teacher at Duel Academy, and the head of its Obelisk Blue group. He is very strict, believing that weaker students who cannot keep up with his lessons should quit or be expelled. He especially dislikes Jaden, having been defeated by him during the latter's entrance exam. However, his attempts to show up or expel Jaden have only humiliated himself and his followers, while making Jaden look better and better. Crowler eventually appreciates his students and in turn is respected for his noble actions. Crowler plays an Ancient Gear deck.