Lushun experienced a total collapse of its social and cultural foundations during the Long Night.
A garden world, it did not need a technological base to remain habitable.
Its cultures have fractured, mutated, and recombined countless times over the centuries of the Long Night, leaving a multicultural world that is more inscrutable and inimical to off-worlders than any pre-Mandate species ever was.
It is officially quarantined by all the major powers in the sector, and no one is known to have returned from its surface in hundreds of years.