On stardate 51825, the Federation starship USS Valiant conducted a mission to collect technical data on a new battleship operating in their sector. After spending three hours collecting data on the vessel, they determined that it was a direct threat to every Federation outpost and colony within fifty light years and that it had to be destroyed. Believing they found a weakness in the design of the ship, they engaged the Jem'Hadar vessel and were subsequently destroyed with relative ease by the battleship leaving only Jake Sisko, Nog, and a Red Squad cadet, Dorian Collins left to escape. (DS9: "Valiant")
Several of these ships participated in the Battle of Cardassia. Afterward, they and the other Dominion forces retreated to the orbit of Cardassia Prime to join the defense of that planet. (DS9: "What You Leave Behind")
The crew of the USS Valiant determined that the primary support braces for the antimatter storage system of the battleship were constructed from viterium, prone to destabilization when exposed to delta radiation. The Valiant crew attempted to exploit this possible design flaw using modified torpedoes, but discovered that the ship was not as susceptible as they thought. (DS9: "Valiant")
Background information Edit
The actual size of this vessel is uncertain. Based on Jake Sisko's statement, which Nog confirmed as "accurate," the vessel is 1,284 meters long if taken literally. This is supported by the close-range engagements in "Valiant", which establish a size several times larger than that of the Defiant-class. The same approximate scale is maintained for the battleships during the Battle of Cardassia. However, in the final shot of the Dominion fleet around Cardassia, the battleship was scaled several times larger than previous. Although this was likely done to enhance the ominous effect of the fleet, it may suggest visually similar classes of varying sizes, much like the K'vort-class and B'rel-class Klingon Bird-of-Prey.
The script for the episode "Valiant" called for shots of the USS Valiant making strafing runs on the Jem'Hadar battleship, taking it extremely close to the surface of the enemy vessel. "If possible we would have used the physical model for both the cruiser and the Battleship, with the scale of the model being the only difference.(...)Since the story called for close up attacks, the camera would have to be flying an inch or so off of the physical model. This was pretty much impossible with the motion control camera/rig and more importantly, the physical model was never constructed to tolerate that kind of close up scrutiny. It just did not have the detail to hold up," David Stipes remembers on his blog.  The only other available model at the time, VisionArt's CGI model, was not up to the task either for the same reasons. It was therefore decided to have a new model built in CGI, the second new studio model for DS9 with no physical counterpart. The Dominion battleship was designed by John Eaves,    along the same lineage lines of the Jem'Hadar battle cruiser, its close resemblance later causing the two models to be sometimes confused with each other. wbm After the design got its final approval in March 1998, the task of building the CG model was contracted out to Digital Muse. The extra added detail, texture and surfacing needed for this episode, would work to its disadvantage in later appearances, betraying the model as being CG when used in medium to long range shots.
- WizKids released a model of the Jem'Hadar battleship as part of its Star Trek: Tactics line. The Star Trek: The Official Starships Collection provisionally lists the Jem'Hadar battleship as a possible release.