Terra is the homeworld of humanity and remains under the influence of the Roman Empire. Its most developed city is known to be Rome. The Via Imperii I jump gate and the Terra Gateway orbit the planet, and among all star systems, Terra holds the largest population.

Mars is considered a world connected to Mars, the god of war, and serves as the center of Rome's military infrastructure. Its natural environment is similar to Terra, though a significant portion remains undeveloped and exists as desert terrain. It was the third extraterrestrial world conquered by humanity after venturing into space, following Luna. In orbit around Mars, the Mars Gateway and several orbital shipyards exist, and most legion-related vessels are produced and maintained here.

Luna is the largest material production hub in the Terra-based industrial network. Large-scale metal processing and construction of massive structures, tasks too demanding for Terra, are handled here, and most of the basic materials required for colony construction and gateway maintenance are supplied from Luna.

The main industrial zone is centered around Sinus Medii. In this area, mining, smelting, processing, and loading are integrated into a single continuous workflow, and produced materials are transported via dedicated transit facilities to the Luna-Terra L1 collection hub. The L1 collection hub serves as a relay point connecting logistics between Terra and multiple planets.

Energy is sourced from polar power generation zones, and the Luna industrial zone and L1 collection hub operate as a unified system. This system enables stable large-scale material production outside Terra and serves as the foundation for transporting resources to multiple planets, supporting the entire Terra-based space industry.

The planet Vesta is one of the primary strongholds of the Vestal Virgins, alongside Terra. Located in Lavinium System, the first external star system ever reached by humanity, it was the earliest colony world to be settled there. The Vesta Gateway and a jump gate orbit the planet.

While the influence of the Vestal Virgins is strongest here, Vesta also maintains the closest ties to Rome after Mars, making it an exceptionally stable colony world. Thanks to its largely beautiful natural environment, many people visit for leisure and travel. Numerous villas owned by Roman nobles are located here, and these estates, set against stunning natural landscapes, serve as symbols of wealth and prestige.

Vulcanus is a remote industrial colony where powerful aristocrats operate enormous heavy-metal extraction complexes using vast numbers of slaves. The planet is infamous for its harsh environment and grueling labor conditions, making it a place few willingly visit.

Slave transports regularly arrive at its small, deteriorated gateway, delivering workers in hypersleep before they are transferred by shuttle to the slave quarters for reawakening. Little is known about the daily reality on Vulcanus, but it is widely believed to be one of the most punishing and exploitative outposts in human expansion, sustained entirely by continuous slave labor and near-total isolation from the outside world.

Terminus is the final planet colonized by Rome and the last destination reachable through the VIA IMPERII network. The Empire's rapid expansion across multiple star systems has placed a heavy strain on its ability to govern distant colonies, and many aristocrats have begun to question the viability of further development on Terminus. However, those who have already invested heavily in its resource extraction projects, real estate ventures, and long-term commercial plans remain determined to push forward, creating growing conflict within the Roman elite.

Orbiting the planet is the Terminus Gateway, where a boundary stone is enshrined. This stone was crafted from meteor fragments found near Alexandria and is used in rituals dedicated to the god Terminus, symbolizing Rome's ongoing expansion into space and the hope for the Empire's continued safety. Although settlers have migrated to the planet, progress remains slow, and living conditions are poorer than on other colonies. The world carries an atmosphere of isolation and quiet resilience, sustained by the settlers' belief that one day meaningful development will finally begin.