Syrus Truesdale's History
Yu-Gi-Oh! GX
Syrus is considered to be the "weaker" younger brother of Zane Truesdale who attends Duel Academy, originally residing in the Slifer Red dormitory along with Chumley Huffington and Jaden Yuki.
Syrus has made progress as a Duelist throughout the series. From the onset, he faced Jaden in preparation for a Tag-Team Duel, but, priding himself on finding a way to outdo his roommate, overlooked the abilities of his own cards. It was for this same reason that Zane forbade him from using the "Power Bond" card, for Syrus was unable to cope with its potential drawback. He and Jaden Dueled the Paradox Brothers and using the Power of Power bond the two won the Duel. He is shown cheering for Jaden in his Duels. When the Shadow Riders first appear, he and Chumley are kidnapped by Nightshroud. After Jaden beats him Nightshroud is revealed to be Atticus Rhodes, the older brother of Alexis. When Duel monsters sprit day is going on, he beats the Dark magician girl in person. He and Chazz provide the commentary for her and Jaden's Duel which Jaden wins in the end. After the Duel was over she gave him a kiss on the cheek.At the start of the second season, he joins Chazz and Alexis to watch Jaden duel Aster. Jaden wins the Duel and Syrus is surprised that Aster lost. Later on, Syrus is given an opportunity to advance to Ra Yellow, should he be able to defeat Missy. Feeling that he should not shoulder his brother's legacy, Syrus gives his "Power Bond" card to Chazz
to pass to Jaden before the start of the Duel, though Jaden convinces him to put it back in his Deck after the Duel.
In episode 55, Syrus develops a rivalry with Tyranno Hassleberry over which of the two is better suited to being Jaden's best friend (in the Japanese version, it is over who has the right to call him "big brother"). They constantly argue and fight, prompting their repetitive separation by Alexis Rhodes. By episode 64, their rivalry comes to a temporary halt, when the two Duel to settle matters once and for all. Before the last blow is dealt, Tyranno discovers that Syrus went without food or sleep to search for Jaden, who had gone missing since his defeat at the hands of Aster Phoenix. Seeing Syrus' devotion to their friend, he chose not to activate his "Jurassic Impact" card, which would have wiped both players out simultaneously.During the field trip to Domino City, Syrus teams up with Tyranno in a Duel against the first duo of The Light Brigade, Frost and Thunder. Although the two are pinned down by their opponents, who tuned their Decks specifically to combat their cards, they end up pooling their efforts to combine their monsters into "Super Vehicroid Rex Union". Despite their teamwork, however, Frost ends the Duel by wiping out all players but himself, and promptly drags them to his master's lair, from where they are transported to Kaiba Land as bait for Jaden and Aster by order of Sarina.
As he observes his brother's actions following his "rebirth," Syrus notes Zane's newfound disrespect for his own cards and opponents. He dismisses the barbaric persona, refusing to believe that his brother has sunk so low. Determined to bring his brother back to his senses, Syrus acknowledges the inevitability that the two of them will face one another. During the Genex Tournament, Syrus and Zane Duel, they are hooked up to electrodes, just as Zane and Mad Dog were in the Underground Duel. Despite his best efforts and Jaden's secret move to place "Power Bond" back into his Deck, Syrus loses, but he does not give up in hoping that his brother can be returned to his former self.
Shortly after the beginning of the third year at Duel Academy, Syrus advances to Obelisk Blue. As a result of Survival Duels being called for by Thelonious Viper, Syrus becomes self-conscious of his worthiness to wear the outfit of the elites, and sets out to prove himself. In the Japanese version, he also wishes to adopt his brother's discarded title, and thus merit the name of "Kaiser Sho" (カイザー翔, Kaizā Shō). Inspired by Jaden's match with Axel Brodie, however, he decides to remain in Ra Yellow, and sets aside his goal for the future. (In the English version he quits the Obelisk Blue dorm stating that Blue wasn't his color and he left Blue to protect Jaden). After Duel Academy is transported to the first alternate dimension, Syrus falls to the Duel Ghouls and becomes one himself.
Later, when Jaden and company venture into another alternate dimension to rescue Jesse Anderson, Syrus is the only one of Jaden's closest friends who isn't sacrificed by Brron. After Jaden wins, he verbally scorns Jaden saying he wants nothing to do with him and up leaving him. While separated from the others, Syrus decides to act as an observer, but later reunites with Aster and Zane when Jaden is released from his possession. After Zane loses to a Yubel-possessed Jesse, Syrus watches Zane die and fade into particles of light before breaking down in tears.
In season 4 Syrus advanced to Obelisk Blue again. Syrus later attempts to finish Zane's Duel with Makoto Inotsume after Zane becomes too weak to Duel, but immediately regrets his decision later as he begins to develop the same heart problems as Zane because of his use of the "Cyberdark" Deck. However, Syrus manages to overcome his problems and defeat Inotsume, thus inheriting Zane's Cyber Dragon Deck later on and promises to improve it. However, he still later falls to Trueman, and is absorbed into the World of Darkness.
It is shown within the World of Darkness that Syrus fears that he will be unsuccessful at creating a Cyber Art Pro League with Zane (as it is his brother's dream) and that he will have to be the successor of the Cyber Art when Zane becomes greatly ill (as Zane has his limits). He also fears that he will be unable to make this dream come true due to few to no people and sponsors being interested in it. It is also shown that if Zane dies when Syrus is still unsuccessful at creating a great Pro League, then he will feel relieved that he is finally released from trying to create something he couldn't succeed at creating. When Jaden calls out to everyone trapped in the World of Darkness, reminding them about the cards that are always there to suport them, Syrus looks at his "Power Bond" card and realises that even though the Cyber Style Pro League may not be much at the start, he can work hard to make it a success. He is revived before Jaden defeats Nightshroud.
Yu-Gi-Oh! 5D's
In the Yu-Gi-Oh! 5D's dub, Blister mentions Truesdale as one of the Duelist he wanted to Duel in the Pro League. Whether this was meant to imply Syrus, Zane or both of them is unknown.