Princess Kupacious (known as Princess Kupacius in her first and last appearances) was the ruler of Shanazar. Extremely ugly and nasty, the toad-like ruler reigned over her city with complete selfishness. Her unwillingness to hand out rewards and the treatment of her staff gave her few admirers. Despite this, she still had loyal subjects who pursued her interests to the very end. She currently lives on Mobius as a frog, ruling over a pond.
Kupacious had been the ruler of Shanazar for many years, presumably having the position bestowed upon her by her missing father. In this time, she had a reputation of being a ruthless princess and very few people tried to cross her. Even so, her kingdom was in slight disrepair, with the state of her main city being primitive compared to settlements on Mobius. Things would change with the sudden appearance of Doctor Kintobor, a kindly Mobian merely stranded within the planet's vast deserts. Kintobor used his scientific ability to improve the plumbing system of Shanazar. Impressed, Kupacious made Kintobor her Grand Vizier (second-in-command).
The first mission she gave to Kintobor was to send him to his certain death. Along with "pet" Sonic the Hedgehog, Kintobor was to take the chosen children to the Mystic Mountain in order to collect their genies. During the mission, Kupacious heard no word of what had happened. Suddenly, her Grand Vizier returned in the form of Doctor Robotnik, who would have been perfectly happy to divulge Sonic's criminal activity. For this, Kupacious posted wanted flyers across the city demanding the capture of Sonic (although there was no reward). While she waited, she continued to send her Imperial Guards to catch other felons, such as Kassim, a thief who wished to steal Kupacious' gems (which she herself had stolen). The princess eventually lost her patience, demanding Sonic's capture by the end of the week or her servants would be placed in the dungeons instead. Fortunately, Sonic took this moment to infiltrate the palace in search of the Transportation Belt and was captured. Kupacious wasn't so happy, however, when Grimer allowed him to escape using his own keys. Her temper was quelled somewhat by Robotnik hiring relentless mercenaries Death-Trap to arrest him.
Several weeks later, Kupacious seemed to have forgotten all about Sonic. She grew closer to Robotnik, accepting a fine necklace from him and went on a "royal walkabout" to parade her new gift. She soon heard of Robotnik's plan to merge Shanazar with Mobius and angrily demanded to rule the new world herself. When Robotnik called her an "ex-princess", Kupacious assumed treason and demanded that her guards behead the Grand Vizier. Unfortunately, the command was another to set off the magic gems in her necklace, turning her into a frog. Her part wasn't over yet; boiling with anger at suddenly being removed from power, she waited until Robotnik had forgotten about her before stealing the Magic Gem that protects all holders from danger. Once the Dimension Blender had done its work, Kupacious found herself stranded at an idyllic pond in a green area. Armed with her magic gem and a new crown, Kupacious started life as a new ruler - over other frogs!