The Callas Republic is an independent grouping of star systems allied with the Alliance.
Background
One of the smaller human polities involved in the Alliance-Syndicate Worlds War, the Callas Republic is an independant grouping of star systems, located on the Alliance World's side of the Alliance/Syndicate border. A Faction that was allied with the alliances for the war with the Syndicate and going their war ship with the alliances, however after the war ended the Callas Republic elected new leadership and as a result the co-president Victoria Rione was voted out and the new government decided to leave its remaining ships and sailors with the fleet so that they would slowly decay through fights and there would be no replacement for their losses.
Once the Alliance Fleet returns from the expedition mission the crews of the Republic ships are near mutiny; last moment orders to dispatch those ships back home help to lessen stress on the fleet. It is mention that the request from the Republic to withdraw from the Alliances is most likely to be granted.
Before the War, the Callas Republic was not considered a major power, and presumably decided to enter the war at some point subsequent to the initiation of hostilities, as the Republic was still neutral at the time when Geary's escort force was ambushed at Grendel in the opening series of Syndicate attacks.
Captains commanding vessels of the Callas Republic and Rift Federation navies were even more initially skeptical of John Geary's legend when he initially assumed command over the damaged remnants of the joint Alliance/Republic/Federation fleet following the disastrous opening stages of the First Battle of Prime.