Besides their feline characteristics, Mephitisoids are widely known for their natural ability to produce mind-influencing pheromones. These pheromones are powerful and complex enough to practically enslave the minds of other sentient beings. The males of the species are especially known for this ability, but because the females are said to only use it during mating. Fear of this ability is what motivates the Shi'ar Empire to quarantine the Mephitisoids on their homeworld of Tryl'sart under martial law.
Pheromones also play a large factor in how Mephitisoids communicate with each other. This is so much so that a Mephitisoid's true name is a unique combination of pheromones. The spoken name of a Mephitisoid is usually something made up for those sentient beings who cannot understand pheromones.
Over a millennia ago, the Mephitisoids were a galaxy-spanning empire. The expansion of their empire eventually clashed with the expansion of another empire, the Shi'ar. This sparked a fierce war between the two alien races. The Mephitisoid army was led by a man known to the Shi'ar simply as the Mephitisoid, and it appeared that he would lead his people to victory over the Shi'ar. But the war turned in the Shi'ar's favor after the young Admiral Alabar used a distilled version of the Mephitisoids' pheromones to lead his Shi'ar soldiers on a victorious campaign. As winners of the war, the Shi'ar would write their own version of this history that omitted Alabar's use of pheromones and painted the Mephitisoids as a race of cruel barbarians.
The Mephitisoids' territory, including their own homeworld, was annexed by the Shi'ar. The Mephitisoids themselves were forbidden from leaving their homeworld due to fears that they would be able to use their pheromone ability to lead a revolution against the Shi'ar. This was too great a threat for the Shi'ar to allow, so for the centuries since the war, they have forced the Mephitisoids to live under martial law on the planet Tryl'sart, which was named such by the Shi'ar.