Several weeks later, Seskal piloted a stolen Jem'Hadar attack ship that transported Damar, Elim Garak, and Kira Nerys to Cardassia Prime for a meeting with Gul Revok and Legate Goris. He informed Damar that orbital traffic control was asking for their security clearance. Fortunately, Garak was able to transmit the right codes. Seskal wished Damar, Garak, and Kira good luck just before they transported to the surface to meet with Revok, leaving Seskal in charge of the ship.
However, Revok had informed the Dominion of Damar's visit, and Seskal and the crew of the attack ship came under fire by the Jem'Hadar and the Breen. Seskal was unable to lower the attack ship's shields to beam Damar's team back. Seskal tried valiantly to return fire, but the ship was destroyed, and he was killed. (DS9: "The Dogs of War")
Background information Edit
Seskal wasn't included at all in the first draft script of "When It Rains…" (dated 8 February 1999), suggesting that his character wasn't yet conceived at the time that script was written. Instead of conflict between Seskal and Kira, the teleplay featured tensions between Kira and Damar. Seskal was inserted into the story by the time the final draft of the "When It Rains…" script was issued (on 16 February 1999). 
Seskal had only one scene in the first draft script of "The Dogs of War", which was in the teaser, and his fate was considerably different from how he ends up in the final version of the episode. In the teleplay, he was one of multiple victims of a massacre in Damar's base on Vanden Prime, where he was found, in the aftermath of the attack, by Damar, Garak, and Kira. Seskal was barely alive when they discovered him, a Jem'Hadar knife in his chest. Although Damar and Kira brought Seskal medical aid from elsewhere in the ruined base, one of his neck tendons had been severed, with surgical precision; he implied to Damar that he had been tortured for not admitting where Damar had meanwhile been. With his final dying words, Seskal advised Damar not to let the Dominion find him and told Damar he was "the only hope Cardassia has."