Umbria is the crown jewel of the Republic and the homeworld of the Umbrian people. Sixty percent of its surface is covered by ocean, while the remainder is made up of continents and island chains featuring lush vegetation, striking rocky outcroppings, and verdant grassy plains. Its capital, Perugia, is the capital of the Umbrian Republic and home to the Republic's Senate and Triumvirate, or executive body.

Called the ‘Gateway to the Frontier’, Tratirne is a near-perfect facsimile for conditions on Umbria itself. Its surface area upends the traditional distribution between water and landmass, with the former only making up about 35% of the surface’s volume, trapped in broad inland seas connected by narrow isthmuses.

From a distance, Tasovo appears as a bright, hot, red-tan marble orbiting its parent white sequence star, Roshia. An unlikely candidate for life, Tasovo would none-the-less support the growth and development of a variety of aquatic and amphibious species in its dark brackish lakes. The rest of the planet is comprised of barren plains and expansive salt flats, baked by the constant bombardment of its sun's UV rays.

Ozenuso is a temperate, life-bearing moon in the Sieva system. Orbiting the ice giant Ormenta, the world is tidally heated by its parent planet, while also capturing significant energy from the system's blue-white star. The ice giant's strong magnetic fields protect the moon from the star's fierce radiation, while its intense luminosity has been a boon for Ozenuso's plant life.

A cold dreary rock of a world, Orvieto nevertheless proved to be an important target for colonization during the early years of the Republic's first expansion into the wider galaxy. Scans of the terrestrial giant revealed mineral deposits in sufficient quantities to fuel further expansion. It also possessed a very active vulcanism, with tons of molten material deposited on its surface every year.

A tropical paradise amongst the stars, Navepico was a smaller terrestrial world located in the heart of the Frontier. First surveyed in 31083, the planet's first visitors sent back reports of strange blue beaches and lush vegetation scattered across its hundreds of archipelagos. it would not take long for more detailed expeditions to descend on the planet, confirming initial findings and beginning the process of documenting a fantastic variety of life.