The only head of the Obsidian Order who lived long enough to retire, Tain was a stubborn, wily survivor who epitomized the efficiently ruthless agency and thrived on the labyrinthine intrigue of his people -- a man the regular military's Central Command dared not challenge.
Hoping for a comeback from his retirement in 2368 to the Arawath colony and Unefra III, Tain engineered a disastrous joint attack on the Dominion and the Founders' homeworld three years later. The Obsidian Order alligned with the Romulan Tal'Shiar in a plot doomed early on by unknown, shapeshifter infiltrators.
Tain was thought dead, until 2373, when he was discovered at Dominion Internment Camp 371 by his son, Garak. On Tain's deathbed, Garak asked but did not get his father's forgiveness. Tain had groomed Garak as his successor, until the events that led to Garak's banishment, which left Tain feeling betrayed; he retired soon after.
But on the eve of the Dominion debacle,Taid had even tried to arrange the murders of Garak and six others who had information on him. In typical Cardassian irony and obfuscation, both Tain and Garak had been ready to trust each other anew in their later years, and Tain aided Bashir's treatment of his son's fatal degenerative bio-implant.
Tain's housekeeper and confidant for over 30 years was Mila, who oversaw him as an older man until the Dominion invasion.