Shiss are four armed, bipedal lizards with wings attached to the primary arm pair but are not capable of flight. They are strictly ruled by a Caste System, based on the color the throat skin of a Shiss male. The female of the species has no such coloration. The colors, in descending order, are White, Beige, Yellow, Green, Red, Blue and the lowest caste is Purple.
Shiss colonize new worlds by first dumping a few loads of Purple Throat Shiss on any marginally suitable world. Shiss don’t survey planets as the Union does. No one checks if the conditions are survivable or if the world is already occupied. They are left with marginal tools, weapons, and supplies and then check periodically if the colony takes hold or if more Purples need to be sent.
Once a colony thrives Upper Caste Shiss move in expecting to be given all the fruits of Purple Shiss labor. Purples are then allowed to serve their masters as slaves on a world they made liveable.
The Purples did not want to lose all they built and had no interest in giving up all their freedoms and possessions just because a Prince from a higher Caste decided to take it. 33 of the Outer Colonies rebelled and the All-White-Nestling dispatched a punishment fleet to eradicate the 33 colonies. One colony was orbital bombed and every single colonist died.
Instead of giving up and take this example as a sign to comply and end the revolution. the elected leaders of 32 colonies approached the United Stars for membership and got full protection from the fleet.
The Union fleet fought valiantly for the Shiss and won. The 33rd Colony had become a symbol of defiance and their freedom, so they turned the entire planet into a Shrine where many Union Shiss travel to pay their respect and to celebrate the Day of Defiance.