Koji Fujibayashi

Koji Fujibayashi (藤林耕史 Fujibayashi Kōji) is a main character of Five. His epithet is "Bullettrain". Koji's speciality is Riding Duels, with his riding skills being comparable even to those of professional riders.

On his character

 * He's very friendly and easy-going, and easily befriends people. He's got a long list of aquaintances, many of which may appear through the story, though Itto is his closest friend and one of few people who knows his secrets.
 * He's very playful, notably when dueling - making puns, jokes and even singing as he duels. This makes a good contrast for when Koji's in a tense situation and must duel seriously.
 * Loves riding a motorcycle and has amazing skills, but ironically he hates cars and is terrible driving one. He's won riding competitions here and there, but he actually doesn't like competing and rides just for fun. He makes a quick revision on his bike after each race/duel.

Backstory

 * Koji is, in fact, homosexual; however, he's reluctant about accepting himself and this troubles him a lot. He's very discreet and doesn't actually date other men because he's hesitant to accept his sexuality.
 * He's only ever told his to very few people, including three guys who were his best friends. However, after learning this, two of them virtually abandoned Koji, while Itto was the only one who stayed on his side.
 * Despite easily befriending people, Koji also has a hard time forming a deep bond with someone - because despite trusting his friends, he's afraid of how differently they could possibly act towards him if they knew about his sexuality.
 * At the beginning of the story, Koji will still be very troubled by this and doesn't know how to deal with it. However, he should be developed through the story and slowly mature.

Canon Deck
Koji runs a Machimal Deck ("Mach" + "Animal"), a Deck featuring the fastest beasts and machines of the world. His playing style consists of quick effects that are Chained to his opponent's moves, in a way that Koji's effects "outspeed" the opponent's and resolve before them. This playing style makes it so that Koji basically doesn't use his own turn, but instead, makes his big moves during the opponent's turn.

One of Koji's favorite moves is bringing out his "Machimal Chimera Rocket G.R.Y.P.H.O.N." in response to an opponent's Special Summon effect that sets up the Summon of a boss monster. Using his quick Fusion effects, he can Fusion Summon immediately before his opponent's Special Summon, destroying their materials before the opponent can even Summon their boss monster. However, his true ace monster is "Machimal Chimera Jet C.E.R.B.E.R.U.S.", which he first shows against Itto - a monster that manipulates the order in which Chain Links resolve, making it so that Koji's monsters are always the fastest.

With the "Machimal" archetype including a very wide array of Extra Deck monsters - in fact, being a unique archetype with more Extra Deck members than Main Deck ones - Koji initially plays predominantly the multi-material "Chimera" Fusions (in contrast to the single-material Metalmorph Fusions). However, to keep his moves unpredictable, he sometimes switches his Extra Deck monsters, for example, including the usage of Synchros for the special Event held by the Earth admin in the climax of Phase 1.

Helpful links:
 * Fastest animals in the world
 * Koji Main Deck Monster Formula

Other Extra Deck "Machimal" monsters which Koji doesn't include in his initial Deck:

Discarded first concept
Koji runs a Sonic Fusion Deck, which makes high-speed plays during the opponent's turn. His Main Deck monsters are based on the fastest animals in the world, while his Extra Deck monsters are based on the fastest machines.

Edit: His Main Deck monsters are WIND Beast-Type "Supersonic" monsters, while his Extra Deck monsters are WIND Machine-Type "Hypersonic" monsters. His Synchro Monsters let a Fusion Monster be treated as a tuner for their Summon (making the Fusions be right away tuners would spoil it from the beginning).