The Junk Planet Kess

During the final era of the Star Empire of Mankind; there was a nexus of various trade routes in the form of an unusual low-metallicity main sequence star which before the intervention of the star people had only a single sub-terran terrestrial planet and an asteroid belt; said planet was dismantled in order to construct a more useful multi-station complex of habitats, housing a local population whose economy served large numbers of passing trade fleets.

The lightweight trading ships of the Star Empire produced a lot of material which couldn't not be recycled onboard the actual ship; and so it was common practice to exchange recyclable garbage for credit at waystations, who would locally store large masses of this trash in orbits for later utilization

When the Star Empire collapsed; it happened all at once- all their powerful magics and technologies ceased to function through some widespread attack, the nature of which is not fully understood.

But at this particular highly traffic waystation; before anyone could suffocate inside their new steel tombs; huge numbers of ships which could no longer steer themselves began to crash both into one another, and worse, into sections of the station complex

Each crash ejected huge amounts of material, which became like bullets in orbit that in turn shredded other structures. Over the next half million years or so; this massive cloud of material began to accrete, drawing in asteroids and space dust in addition to station chunks and garbage; coalescing into the planet 'Kess'