Alashan

The Alashans were an ancient race native to a Wild Space planet of the same name. The race had reached technological sophistication at a time well before the formation of the Galactic Republic. Among their accomplishments was the creation of a power source that was able to power the entirety of their massive underground city of Forever. The power was also the source behind the Guardian of Forever, a powerful energy being designed to protect the city. Among other powers, the creature was able to fire a superlaser using the power of the city's control center which could destroy a target a hundred thousand kilometers from the planet's surface.

By the time of the Galactic Civil War, they had completely disappeared. Leaving the gigantic city of Forever as the only monument to their existence, the Alashans sealed the city from the outside.