Kiryu

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The group would go around battling rival duel gangs (In the English dub, The Enforcers defeat Satellite gangs in order to make Satellite a safer place; after defeating all the gangs, Kalin finds Security as the enemy). As time went on however, he became a bit more sadistic against his opponents and started going out of control and hurting his opponents as a result, which caused Crow, Jack and Yusei to leave. Kalin decides to provoke Security and attacks a Security officer. When Yusei tries to take the blame for it, his attempt fails and Kalin is arrested. Misunderstanding the situation and believing Yusei had sold him out, he later becomes a Dark Signer, branded with the Giant birthmark, in order to get his revenge on Yusei. Their first duel is canceled due to a malfunction on Yusei's Duel Runner, but he loses his second duel with Yusei, when Yusei's feelings allows him to synchro summon Majestic Star Dragon. He forgives Yusei before disappearing. In the 4kids version he admits he was wrong to think that Yusei sold him out. ======

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He is revived after Goodwin's defeat, but still has memories of being a Dark Signer and the crimes he committed. He goes to a place called Crash Town looking for a way to die, and ends up dueling Yusei again. They are soon both captured and taken to work in a mine, though Yusei manages to free him. While assisting two siblings, West and Nico, in rescuing their father, Kalin regains his will to live. ======

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In the manga, Kalin was once a prisoner in a facility owned by Rex Goodwin. He and Jack Atlas dueled each other to earn their freedom but Kalin threw the match as he didn't want to leave the other kids behind. As a reward for winning, Goodwin gave a Duel Dragon card to Jack. Annoyed by this, Kalin steals the card and destroy the facility with explosives. Kalin would meet Jack years later and gives back the card he stole from him. Then they decide to have a Duel to settle the scores between them. ======

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He uses an "Infernity" Deck that specializes in effects when the player has 0 cards in his hand. His Dark Signer deck additionally has two key monsters: a Dark Synchro Monster called Hundred Eyes Dragon, which can gain the effects of the monsters in his graveyard, and the Earthbound Immortal Ccapac Apu, which inflicts additional damage for every monster it destroys. His Dark Signer birthmark is based on the giant Nazca line. In Crash Town, it is revealed that he has his own Ace, the Synchro Monster Infernity Doom Dragon. In the manga, Kalin still uses an Infernity deck but with new monsters and he supports his deck with the Void trap card series. His Ace monster is the Duel Dragon: Void Ogre Dragon. ======