Seyllin I is a planetary mass in the Seyllin system in the Gallente Federation. It was once a barren, blasted world that was nevertheless colonized and exploited for its massive heavy metal resources. The planet was destroyed during an event known as the Seyllin Incident, rending it little more than a fractured collection of coalescing rubble.
Deep within Federation space, Seyllin I was devoid of any atmosphere, a hellish world whose daytime temperatures soared high enough to turn lead into molten slag. Underneath the surface was an abundance of heavy metals that drew Braggs Seyllin to found a community here. In the mined excavation sites where thick veins of precious ore once lay, intersecting caverns big enough to house capital ships were illuminated in gentle cycles with artificial sunlight; water ran in streams and falls throughout a cityscape that was equal parts lush vegetation and stylish living quarters; atmosphere scrubbers worked with the ecosystem to recycle air and push a comfortable breeze throughout the miles of interconnecting city blocks and work centers.
Its four main cities, Lodecore, Metal City, Southern Cross, and Valimor were thriving, pulsing cityscapes interconnected by magrail systems that spanned around the entire planet. Access points for each of the main cities littered the surface of Seyllin I. The most common of these were spaceports, which allowed dropships to transfer passengers and cargo within the safety of shielded containment fields.
The planet hosted several space elevators for heavy freight, but these could only be operated at night due to the extreme daytime temperatures. Just beneath these access points was a network of operational support structures and the Cassandra monitoring site.
On March 10, YC111, the planet was struck by two consecutive disasters originating from its sun. The first, which struck at around 8:49 EVE Standard Time, was a pulse of radiation that killed thousands on the planet's sun-side surface and caused acute radiation poisoning in those beneath the sun-side surface. The second occurred several hours later, when a large mass of plasma ejected from the star struck the planet. The collision destroyed the planet, killing the population that had not been evacuated.
Following the planet's destruction, its remnants remained gravitationally bound and slowly began to collapse back into a planet. Once this process is complete, the planet's structure could be drastically changed, but should still contain the majority of its metal deposits. However, this process is expected to take thousands of years.