During his time as a Dark Signer, Kalin wore the black robe of the Dark Signers that was accented with blue stripes. His dark mark was the Giant. He had extreme hatred toward Yusei Fudo and his previous team (The Enforcers), but later forgave them after he found out the truth from his loss to Yusei. He was brought back to life after Goodwin's defeat. He was last seen in Crash Town, where Kalin attempted suicide by dueling in order to atone for his wrongdoing, only to be forgiven for them by his former teammates, Yusei Fudo, Jack Atlas and Crow Hogan. He later stayed behind to help rebuild the town along with West and Nico, which was later renamed Satisfaction Town to cherish his team's honor.
Originally, Kalin started as a cheerful and good person, who looked out for his teammates and gave hope to them. But after his team conquered the entire city of Satellite, Kalin became obsessed with protecting what they worked so hard to obtain, and grew paranoid into believing that any duel gangs not under his control were a threat to the order they had brought. This caused him to begin dueling people recklessly including kids, which harmed them in the process, and which eventually lead him to challenge the city's security, which caused his downfall. Kalin was captured by them and sent to prison to die and blamed Yusei for his betrayal and capture.
As a Dark Signer, his personality had become even more crazed, which resulted in him bursting out in insane laughter at his opponents' and enemies' pain and misery. He also showed great hatred towards his former teammates, Jack Atlas, Crow Hogan, and especially Yusei Fudo, to whom he would often call a traitor and exclaimed "You betrayed me!"
After his death and revival, he came to realize that all his pain had come from his own mistakes, and made him regret what he had done in the past. Depressed and guilty, he ventured out to Crash Town and looked for a place to die, and was uncaring of what befell him. His method of dueling showed that as his monster's effects acted like Russian Roulette. But after seeing Yusei and the kids, West and Nico attempting to save him, Kalin regained his self-worth and kindness as he vowed to protect them and all the citizens of Crash Town.
When a Dark Signer, Kalin was able to project his Earthbound Immortal into fog as a purple image, which also caused Yusei's mark to react. Even after being revived as a normal person again, he was still capable of inflicting real damage to an extent, as his "Infernity Des Gunman"s attack was strong enough to fully knock out Lotten.
Kalin was once the leader of The Enforcers (Team Satisfaction in the original version), which consisted of himself, Yusei Fudo, Crow Hogan and Jack Atlas. He met with the trio for the first time when he approached them with the idea for the Team. He fought for his own ideals and unique sense of unity and gave his team a true glimpse of hope under the despairing circumstances of the Satellite.
The team managed to conquer all the team areas in the Satellite. During the face-off with the final gang, one of them almost killed Yusei by pushing him off the roof, but Kalin saved him.
After conquering all the zones in Satellite, Kalin got into a fight with a kid from Team Insect, something that prompted Crow and Jack to go against Kalin and leave the team. Later, when Sector Security began arresting duelists in Satellite, Kalin decided to take action into his own hands and blew up a part of the Security base, and he seemed happy that he did it. At this point, Yusei left as well. The abandonment felt at the Enforcers' dissolution caused Kalin to become obsessed with ruling Satellite forever and reuniting his group for their last Duel against Security. He was eventually pursued by Security until his former teammates came to his rescue. However, neither Crow, Jack or Yusei believed they could defeat Security, so Kalin confronted a Security guard on a Duel Runner and ended up driving through a bunch of crates, which severely injured the guard. Before he could finish him off, Yusei interfered and isolated him in a room. Yusei then decided to call himself the leader of the Enforcers in the hopes that they wouldn't arrest Kalin. But security found Kalin and arrested him for injuring a guard. One of the Security members had already figured out that Kalin was the leader and Yusei tried to convince that he was the Enforcer's leader; Kalin saw Yusei trying to convince Security to let him go, and he mistakenly believed that Yusei had him purposely arrested. Kalin attempted to fight him, but was held back by Security and was arrested.
In the Facility, Kalin was painfully imprinted with a criminal mark, and the prison guards constantly beat him up and intentionally withheld his food rations. Although he claimed that he could survive the abuse, his resistance was weakened when Security took his Deck, which was his most prized possession. After that, Kalin was seen in a cell, near death from starvation, when a voice spoke to him. It called itself the "Envoy of the Underworld" who came with a proposition: If Kalin had some sort of unfinished business, he could come back to complete it as a Dark Signer. Because of his grudge against Yusei and his wish to fight the last battle with Team Satisfaction, Kalin accepted, died of starvation and was reborn as a Dark Signer. At some point after that, he escaped prison and eventually joined up with the other 3 Dark Signers: Roman, Devack, and Misty. They were all under Roman's leadership.
Kalin was waiting for Yusei who had been accompanied by Crow, and as they both entered the B.A.D. area, Yusei and Crow were both shocked to see him. He jumped on his Duel Runner and created a shadow barrier in the process, which suddenly formed, and separated Crow and Yusei. The barrier began to take the shape of his mark, the Giant. Kalin then exclaimed that he would take down Yusei, as their Shadow Turbo Duel was about to begin.
Before the Duel started, Jack appeared in a helicopter, Kalin exclaimed that the Enforcers were together again. The Duel began with Kalin gaining total control and him telling Yusei to suffer. Throughout the whole duel, Kalin laughed hysterically when referencing their past together. Yusei pleaded with Kalin to stop, and reminded him how he had saved Yusei's life years ago. Yusei still didn't understand why Kalin hated him. Then after Kalin's direct attack, he remembered. Yusei had stopped Kalin from escaping arrest after he almost killed one of the Sector Security's squad members. Yusei Summoned "Stardust Dragon", but Kalin countered by Summoning his Earthbound Immortal "Ccapac Apu", which nearly ended the Duel. However, before he could claim victory, Yusei's Duel Runner malfunctioned, and critically injured Yusei. Upon seeing this, Kalin laughed and ended the duel without a victory, and told Yusei to suffer the same pain that he had endured.
When he returned to the headquarters of the Dark Signers, Roman Goodwin asked him why he did not kill Yusei. Kalin replied that he would do so if all Dark Signers were present. He also said that he would let Yusei live in fear after he witnessed the power of his Earthbound Immortal.
He was present along with the rest of the Dark Signers when they all confronted the Signers right after Yusei's and Roman's first duel concluded. He tried to degrade Yusei by calling him weak, however Yusei's opposite reaction to that comment surprised him.
After Yusei finally arrived at the Giant tower, he and Kalin began their rematch and told him that this would be the Enforcers' last duel. He continued to use his Handless Combo strategy. He eventually Summoned his Dark Synchro Monster "Hundred Eyes Dragon" once again and assaulted Yusei with its effect. After Yusei destroyed it, Kalin revealed to him the horrible incidents that occurred to him while being a prisoner before he became a Dark Signer.
As Kalin said to Yusei that by accepting his fate, he could return to show Yusei the fear that he had felt at the time. Intending to do this through his Earthbound Immortal card, he then Summoned "Ccapac Apu" once again, and tried to finally defeat Yusei with it. However, as Yusei managed to fend off the Earthbound Immortal's assault, the Immortal itself began to trash the ground where the Duel was taking place. As Kalin began to have some difficulties with this, Yusei extended his hand to offer his help, which symbolized the occasion where Kalin risked his life to save Yusei. However, Kalin rejected it, and stated that it was too late and that it was completely pointless. After this, Yusei Summoned "Majestic Star Dragon", and it ultimately took down "Ccapac Apu".
By this, Kalin lost, and in the end, not only did he make peace with Yusei, but also reveals to him that he had another purpose besides revenge when he transformed into a Dark Signer; Kalin also wanted to carry out the Enforcers' Last Duel. Following that, Kalin finally turned to dust.
Kalin was the third Dark Signer to be defeated.
When Rex Goodwin was defeated in the final battle, and the King of the Netherworld was destroyed, Kalin was restored to life, along with the other Dark Signers except for Roman and Goodwin himself.
After these events, he was gone on a trip, according to Luna.
Following the events of the Dark Signers, Kalin resided in a town that was ruled by dueling. His appearance had gradually changed over the course of time; his hair was much longer than before and he wore a trench coat. He also carried around a harmonica around his neck (which he often played) and his personality showed no emotion; when he did show any emotion, it was of sadness, concern, or pity. He followed the gang leader Radley, and a bunch of duelists that dominated part of Crash Town. Barbara told Yusei that Kalin had come to this town to die. Kalin said that he had forgotten the meaning of words such as satisfaction. He dueled one of the members of another gang led by Malcolm and ultimately won against his opponent. After the Duel, Yusei tried to talk to him, but he gave no reply as he rode off with Radley's gang.
After the duel Kalin was in the gang bar, but left so he could be alone. Kalin still had memories of the time when he was a Dark Signer (how this occurred was unknown; it was possible that he remembered because he became a Dark Signer willingly, like Rex and Roman Goodwin, and that unwilling transformations like Carly's resulted in memory loss). Being left with the guilt from what he had done to hurt his friends, he struggled to end his life through the only thing that once mattered to him: dueling. The next day Kalin challenged Yusei and revealed his intentions, and pleaded with him to defeat him so that he could die in the mountain. Kalin fought hard, and refused to simply throw the duel, and even resorted to Summon his "Infernity Doom Dragon". Ultimately, however, he was defeated by "Stardust Dragon" again.
After the duel, Yusei and Kalin were double-crossed by Barbara, who was secretly a member of Malcolm's gang. They were apprehended by the undertakers and taken to the mountain along with Radley after losing to Lawton, Malcolm's brother. Kalin went to work with no second thought; even Yusei couldn't convince him to escape otherwise. Yusei then punched him in the stomach and left him unconscious. He took Kalin and escaped, and as they did, they ran into Nico and West. Soon after, Lawton and Malcolm's gang members found them, Yusei went and Turbo Dueled Lawton, while Kalin was running away with Nico and West in a miner cart from Malcolm's gang members. Kalin managed to steal a Duel Runner from one of the members of Malcolm's gang, and used it to get to the duel between Lawton and Yusei. In an attempt to get rid of them, Lawton threw dynamite at them, which caused the mine to collapse and left Kalin and Yusei in a crevice, while West and Nico were taken as hostages by Lawton. After visiting the graves of those who went to the mountain, Kalin vowed to fight for those either still working in the mountain or had lost their lives because of it and to save West and Nico, and called himself a "Death God". Returning to Crash Town, to the shock of Lawton and the others, he and Yusei engaged in a 2 vs 1 Duel with Lawton, to free the town from his horrid rule. Though their duel was coming to an end, Lawton's men interrupted and proceeded to stop Yusei and Kalin. But the members had a change of heart and decided to hold back. Lawton and Barbara attempted to make a final getaway but were stopped by Crow and Jack. In one last attempt, Lawton detonated the explosives in the city, which created a diversion. Kalin gave chase on Yusei's Duel Runner and caught him in order to finish his last turn. Lawton, knowing his top card was a spell card that would render Kalin's "Infernity Des Gunman" useless, agreed to finish the Duel. But Kalin used the effect of "Infernity Climber" to draw this card instead of his spell card, using Des Gunman's effect, and finished off Lawton. After that, Kalin stayed in town to watch over its reconstruction, and to watch over the kids, West and Nico. In honor of his team, he renamed Crash Town, Satisfaction Town.
In episode 150, he was cheering on Yusei. Two episodes later, Kalin reappeared and was seen being defeated by Jack in Satisfaction Town as Jack was self-training himself to once again regain his crown as the King of Riding Duels. Kalin told Jack that he had become a lot stronger since the days of the Enforcers but he was still not satisfied, to which Jack agreed with.