Bastion Misawa, known in Japan as Daichi Misawa, is a highly analytic Duelist who resides in the Ra Yellow dorm at Duel Academy. Bastion is a mathematic genius who covers his cards and the walls of his room with endless numeric formulas, believing that everything in life can be calculated arithmetically. The neglect of his character is a running gag throughout the series in both incarnations.
Originally a rival and friend of Jaden Yuki, Bastion's role in the anime decreases as each arc passes. Although his role in the manga does not.
Bastion's usual outfit consists of the standard Ra Yellow. His black hair is neatly arranged, with a large portion flushed back and slightly to his left, featuring different layers where the sloping changes direction. He carries an Academy-issued Duel Disk on his left hand.
Despite his protests that such feelings are illogical and irrational, it is implied that Bastion has feelings for several female monster cards seen throughout the series, his primary crush being "White Magician Pikeru", but it is to believe that he is crushing on other cards and other girls, like during the beginning of the "Genex Tournament" he couldn't attack "Familiar-Possessed - Hiita", because he liked her and when a doll named Alice showed up, he wished her to be with him instead of Tyranno Hassleberry. In the English dubs, Bastion speaks with a British accent. In the Japanese version, Bastion occasionally addresses Jaden as "Ichiban-kun" meaning "Number one".
His given name in the Japanese version means "great intellect", reflecting his Dueling style and character.
Bastion came as #1 in the entry examinations and is generally regarded as the best newcomer student. He and Jaden Yuki first met during the examinations, with Jaden referring to him as "#2," and himself as "#1." After seeing Jaden defeat Dr. Crowler, Bastion himself agrees with these titles.
After defeating Chazz Princeton in a public Duel Bastion is offered entrance into Obelisk Blue but declines, saying that he promised himself he would not advance to Obelisk Blue until he was the #1 Duelist of the freshman class and in order to do so, he would have to defeat Jaden, who he viewed as #1. He builds a seventh Deck, seemingly based off his Water Deck which is devoted to sealing certain cards so that an opponent will not be able to summon most of his or her monsters. Bastion uses the seventh Deck against Jaden, preventing the use of "Polymerization" with "Cursed Seal of the Forbidden Spell", therefore keeping Jaden from calling forth his stronger monsters but is still defeated when Jaden uses a combination of "Elemental Hero Wildheart" and "Cyclone Boomerang" to destroy his Spell and Trap cards.
Due to his skill Bastion is one of the seven Duelists that receive a key to the Spirit Gate that can unleash the Sacred Beast cards. Bastion only Duels one of the Shadow Riders, Tania. Although Bastion uses his Magnet monsters, which use opposing plus and minus charges to stop his opponent's attacks and fuse to become stronger, he loses. Afterward, he is stripped of his free will to a degree and becomes infatuated with Tania. He returns to normal after Jaden defeats her and she runs off, leaving her Shadow Charm behind. At one point during the second year, angered by the fact that he was not considered for entry into the Society of Light, Bastion challenges Sartorius to a Duel in order prove his strength and disband the Society. Chazz, however, takes Sartorius' place, and although Bastion has the means of being victorious, Sartorius takes advantage of his self-doubt and desire to be accepted, convincing him to intentionally lose to Chazz and finally join the organization.
Following his conversion, Bastion is relegated to the sidelines, watching helplessly as other Society members are given the opportunity to Duel Jaden and convert other school members into their group, while he himself is assigned no such tasks. He tries to show loyalty to the society by bleaching his hair white, but nobody notices him. When the Genex Tournament started, he tried to challenge Prince Ojin to a battle, but Sartorius battles the latter instead. After weeks of such torture, as well as a conversation with Dr. Eisenstein, he becomes "enlightened" about his worth as a Duelist and as a person and leaves the Society of his own accord to pursue his goals.
After leaving the Society of Light, Bastion follows Eisenstein back to his laboratory and becomes his impromptu apprentice, helping him with an experiment in quantum mechanics. However, the experiment goes wrong, and Bastion is flung into the same alternate world that Jaden and his friends, as well as the entire Duel Academy main building, is pulled into after Jaden's Duel with Professor Viper. There, he wandered the world for an indeterminate amount of time, until he was finally reunited with his friends. When Blair Flannigan is found injured, Bastion offers to help her get the medical attention she needs by locating a submarine he had spotted earlier in his travels, and attempting to use it to get her out of the campus building and to a hospital. After volunteering himself to Jaden and co.'s mission to rescue Jesse Anderson, who was still trapped in an alternate dimension, Bastion meets up with Tania again, who herself was pulled in from her own dimension. The two wander around to protect the dimension's inhabitants. He later comes to inform Jaden about Yubel's plan to unite all 12 dimensions together and then urges Jaden to accept The Supreme King because The Supreme King is a part of his soul, and without him, he won't have the power to stop Yubel.
Bastion decides to stay in the alternate dimension with Tania which is where he is presumed to still be. However, among the silhouetted images of Duelists that Nightshroud shows to Jaden is one that strongly resembles Bastion. He was presumably restored after Jaden defeated Nightshroud.
Bastion has six Decks in the anime, one for each Attribute, though only his EARTH and WATER Decks are ever seen. All his Decks are based on of scientific formulas and processes, and have various control elements to them. Bastion's WATER Deck focuses on "Water Dragon" while his EARTH Deck relies on "Magnet Warriors" and making monsters "Plus" or "Minus" monsters, which affects which enemy monsters they can attack.
In the Society of Light arc, Bastion combines all his previous Decks together, but he is again only seen using cards from his EARTH and WATER Decks. Most of his monsters tend to be based off of scientific processes.
In the manga, he plays a Yōkai Deck, based on Japanese mythological creatures. This Deck relies on discarding monsters from his Deck to the Graveyard to later be revived, activating their effects.
Occasionally during episodes that specifically pit Bastion against Jaden, a picture of a tiger and Chinese dragon, respectively, would appear. These two creatures are represented of the Tao philosophy of Yin and Yang, with the Tiger being Yin, and the Dragon being Yang; similarly, they represent the dichotomy between Bastion's calm, calculated, and orderly way of Dueling, and Jaden's more hectic, impulsive, and erratic Dueling style. Coincidentally, the Shadow Rider Tania, who Bastion falls in love with, has a tiger pet, and is revealed to be a tiger herself; indeed, during Duel Monsters Spirit Day, Bastion dresses up as "Amazoness Tiger" as a tribute to Tania. This further ties Bastion in with the Tiger of Yin symbolism.
While most people in the Society of Light were completely loyal and devoted to Sartorius, Bastion expressed a wish to challenge him, which he did multiple times, in addition he did not act arrogant (which every other member, save Sartorius did) while in the society, and he seems to remember his time in the Society of Light and did not need to be defeated and snap out of the brainwashing to leave implying that he may have faked being brainwashed.