Kallin, a male Human individual, held the rank of Commander within the Coruscant Security Force during the war against Zakuul. After the demise of Empress Vaylin of the Eternal Empire and the subsequent establishment of the Eternal Alliance in 3629 BBY, Kallin, who had connections to the former Supreme Chancellor Leontyne Saresh, became a vocal detractor of the newly formed Alliance. Ultimately, Kallin and his fellow conspirators devised a scheme involving a false-flag operation. Their plot involved bombing the Senate Tower and framing the Alliance for the act. They established their base of operations in the Works, and from there, they reprogrammed several combat droids to serve their purposes. They also procured necessary explosives, some from evidence storage and the remainder from underworld organizations.
However, the Eternal Alliance uncovered Kallin's scheme and took action to intercept him and his confederates. Alliance operatives followed him to his headquarters in the Works, where Kallin underestimated the threat, assuming that the local cthons would provide sufficient protection. Nevertheless, the Alliance forces fought their way through and defeated Kallin's second-in-command, Raena, before confronting Kallin directly. Kallin resisted, but he was eventually defeated and killed.