The Scilla Republic is run by the Scillan Senate on Capitolus. Each planet is run by a similar Senate, with the head of the planetary senate being called Senator of the planet and acting primary envoy to the overall senate on Capitolus.
Disputes between senators are resolved by gladiator matches, in which captured psions are pitched against each other.
The republic takes its name from the pre-historic Earth legend of Scylla and Charybdis, two neighboring monsters. In the earliest days of the republic, the people of Capitolus were in constant competition with what is now Palatinus, with one Senator referring to the two planets as those two monsters, tearing at each other instead of working together. The image stuck, and soon the two opposing troops were called 'Scyllan' or 'Charybdic' forces, respectively. In the end, the forces of Capitolus outmatches those of Palatinus, with the united republic being called the 'Scyllan' republic, first in mocking, then over the centuries as proper name.