Yu-Gi-Oh! 5D's is a Yu-Gi-Oh! anime series, that began airing in Japan on April 2, 2008, as the successor to the Yu-Gi-Oh! GX anime. It was then followed by the Yu-Gi-Oh! ZEXAL anime. It also had a spinoff manga series.
The Duelist Genesis and Duel Terminals were designed to introduce this new anime series to Yu-Gi-Oh! card game players. This series uses game mechanics from the Master Rules. This series introduced the Synchro Summoning mechanic that was then adopted into the trading card game, and the main characters often had Synchro Monsters as the centerpiece of their Duels. Synchro Monsters were also a large part of many parts of the series' plot.
Yu-Gi-Oh! 5D's is set in New Domino City some time after the events concerning Yuugi Mutou and Juudai Yuuki. A new form of dueling, "Turbo Duels", now take place on motorcycles called "Duel Runners". While regular dueling still exists, Turbo Duels have become a popular form of entertainment for spectators, who watch them in specially-designed stadiums. This series also takes place in an altered time-line (due to Iliaster intervening with the past).
Yusei is the main protagonist of the series, a young man who grew up in the Satellite. When he travels to New Domino City in order to retrieve his Stardust Dragon from Jack Atlas, he soon discovers that he is a Signer, a person chosen to bear the mark of the Crimson Dragon. While he initially bears the mark of the Crimson Dragon's tail, it is replaced with the Dragon Head following his battle with Goodwin. Yusei is a cool, attractive, calm and collected duelist who believes no card is useless, and is admired by many people. He values his friends above all. Yusei uses a Junk Deck which focuses on managing small monsters of various levels in order to summon out powerful Synchro Monsters, such as Junk Warrior. His key card is Stardust Dragon and he later obtains two further evolutions: the powerful Majestic Star Dragon and the Accel Synchro monster, Shooting Star Dragon.
Jack is known as the "King of Riding Duels", and was once Yusei's best friend. However, they became bitter rivals after Jack stole Yusei's Stardust Dragon, Duel Runner and left for New Domino City. As a former resident of the Satellite, he must hide his past from the rest of society. Jack is defeated by Yusei in the championship round of the Fortune Cup. He starts off as very arrogant and cruel, but his conscience is revived thanks to Carly Nagisa, who heals his wounded heart and teaches him to "let the real Jack Atlas live", and become a good person. Jack is also revealed to be in love with Carly. His signature card is also a Synchro monster, Red Dragon Archfiend which, when granted the power of the Signers, can be upgraded to Majestic Red Dragon.
Aki is the main female protagonist, and in the first season, she doubles as an antagonist. Aki appears as a cold and pathologically sadomasochistic girl with the power to bring the monsters and magic of Duel Monsters to life, a psychic power ability only used through anguish and cruelty to get revenge on those who mistreated her. Because of her abilities, she is called the "Black Rose Witch". Previously, Aki chose to distance herself from people, believing her power to be caused by the Dragon birthmark she possesses, but she became kinder after her second duel with Yusei, whom she eventually falls in love with. She is the third Signer, who plays a deck based around Plant-Type Monsters, and she holds the "Black Rose Dragon".
Crow is one of Yusei's best friends and a thief. His parents died when he was little, and he was alone until Duel Monsters gave him friends and taught him how to read. He was given the nickname Crow by some other young duelists, since his first card was a Blackwing. He passes his knowledge on to a group of children he looks after, and he steals to provide for them. He later becomes a member of the Team Satisfaction with Yusei, Jack, and Kiryu, but he quits due to Kiryu taking the fun out of dueling. His custom Duel Runner, Blackbird, has a built-in Flying Formation used to cross large gaps and can also fire hooks to change direction. After facing Goodwin alongside Yusei and Jack, Crow inherits Yusei's Tail Birthmark, becoming a Signer. He uses a Blackwing deck that can quickly summon monsters (a.k.a. "swarming") and use their abilities to win a duel, and his main Synchro Monsters are Blackwing Armed Wing, Blackwing - Silverwind the Ascendant, and ]Blackwing Armor Master]. He later obtains his own Signer Dragon, Black-Winged Dragon.
Luca is the calm and collected twin sister of Lua. She plays a "Fairy/Spirit" deck, and gained the ability to speak with Duel Monster spirits after an incident that occurred eight years ago. At a young age, Luca fell into a coma and entered the Realm of Duel Monster Spirits, where she met Ancient Fairy Dragon and promised to protect her. Although she had since forgotten this experience, she comes to remember after the Fortune Cup, and later returns to the Duel Monster Realm to free Ancient Fairy Dragon from Demak's control. She dislikes dueling, as speaking to monster spirits tires her. She is also one of the six Signers. Her birthmark is one of the Crimson Dragon's Claws. Her dragon is Ancient Fairy Dragon, which she retrieved after defeating Demak.
Lua is the lively and blundering twin brother of Luca. He plays a "Morphtronic" deck, with transforming monsters that have different abilities in attack and defense position, and his key card is Power Tool Dragon. He idolizes both Yusei and Jack and is always looking after his sister Luca. During a life-or-death battle against Aporia, Lua's desire to protect Luca makes him the sixth and final Signer, with the Mark of the Crimson Dragon's Heart. He also comes into possession of the true form of Power Tool Dragon, Life Stream Dragon, which is also a Synchro Tuner monster which Yusei can use to summon out his strongest monster, Shooting Quasar Dragon.