In Medieval times, Megakat City was known as Megalith City and it was ruled by Queen Callista, assumed ancestor of modern-day Deputy Mayor Callie Briggs. Queen Callista was the target of the unwanted affections of the Pastmaster, who led a magical siege against the city in an attempt to force the Queen to mary him. Through the use of an an amulet she wore on a chain, Callista herself was a magic wielder, but her abilities were not as advanced as the Pastmaster’s.
For reasons unknown, the SWAT Kats were brought back to the Dark Ages by a time vortex, and encountered the Queen and her guards. At first thinking them enemies, Callista had her guards attack, until Razor withdrew the Dragon Sword from the stone, signifying him as the hero that would defeat the Pastmaster. This also earned Razor Callista’s affections, much to the chagrin of T-Bone.
Callista was later abducted by the Pastmaster, who used a small army of Cyclops monsters to attempt to level Megalith city. In exchange for the safety of the city, Callista agreed to marry the Pastmaster, but quickly withdrew the offer when the SWAT Kats bested the Pastmaster’s forces. As the Pastmaster attempted to escape with his captive aboard a dragon, the SWAT Kats intercepted (ironically with T-Bone making the day-saving shot using a missile with the Dragon Sword attached to it).
Queen Callista was seen again in a flashback in The Deadly Pyramid, in a scene that used new footage with Season 2 style animation. Of note, this scene violates the continuity of Bride of the Pastmaster, showing the wedding ring as gold instead of silver, and the amulet (which had been destroyed earlier in the episode) still intact around her neck.