In Yu-Gi-Oh! 5D's Tag Force 4 Dark Signer Kalin appeared as a Partner character and could only be found between sunset and the end of the day after completing Yusei's story.
Enforcer Kalin Story
To unlock Enforcer Kalin's story, Activate the PSP Recognition and insert Yu-Gi-Oh! GX Tag Force 3. Next, take Kalin to see Lenny at the shoreline and select the option "Look at partner in a new light". Kalin would appear during the daytime.
Dark Signer Kalin Story
Kalin appeared at the Player's house and told him they would eliminate the Signers.
In the first event, the Player and Kalin encountered Crow and Rally Dawson and they challenged them to a Tag Duel to eliminate them, though he was not a Signer.
In the second event, Kalin lured Jack and Luna into a trap and challenged them to a Tag Duel while Leo watched them.
In the third event, Kalin and the Player encountered Yusei and Akiza Izinski and challenged them to a Tag Duel.
In the final event, to the Player's surprise, Kalin challenged him to a duel.
In the end, Kalin had the peace of mind that his friends had grown stronger, and he revealed that he did not succumb to the darkness inside him and was thankful for one last duel. A photo of him, the Player, Crow, Jack and Yusei ended up falling out of his pocket.
Upon completing the story, the Player received three copies of Earthbound Immortal Ccapac Apu and two personal photos: The first is "Kalin Kessler - Last Duel" and the second is "Kalin Kessler - The Enforcers".