Yusei Fudo is the main protagonist of Yu-Gi-Oh! 5D's, one of the Signers, and the current King of Duelists. He is known for and respected by many other characters in the show for his genius style of dueling, his considerable duel skill, and his cool and clever personality. He uses a Duel Runner called Yusei Go. In the English anime, "Let's rev it up!" is a common catchphrase that he uses.
Yusei is usually depicted as being serious, calm and clear-minded; even in very dangerous situations. Due to this he rarely acts on impulse and usually thinks things through before he plays any cards, always trying to stay one step ahead of his opponent. This is made obvious during his duels, as he regularly visualizes card flowcharts in his mind in order to devise his strategies. He is also very close to his friends and very hesitant to put them in harm's way. In the English version, Yusei has had a fear of insects ever since a cockroach nested in his ear, as said by Nervin. He was however able to conquer this fear after his Duel against Lenny.
Yusei was born in the Tops area of New Domino City. His parents were lead developers for the Ener-D Reactor. Dr. Fudo named his son Yusei after the Planetary Particle (Yuusei Ryuushi), as he wished for Yusei to be able to connect people with bonds. As the Zero Reverse was about to take place, before dying, Yusei's father placed Yusei in an escape pod, saving him from the disaster that would follow. Yusei's parents were both killed in the Zero Reverse and Yusei was sent to an orphanage in Satellite, where he was fostered by Martha. Growing up he was interested in auto shop and Jack defended him and his friends from bullies.
Yusei grew up in Satellite, where he befriended Kalin Kessler, Jack Atlas, and Crow Hogan. As residents of Satellite, they were made to do labor for the residents of New Domino City and denied many luxuries, often enjoyed in New Domino.
Being forced to survive on what he could, Yusei developed expert dueling skills. He, along with Kalin, Jack and Crow, became part a group known as the Enforcers (Team Satisfaction in the Japanese version).