Were the vessels made one after another or were they all conceived at once?

Not meaning to bring unwanted dirt but if it was one after another then some of the vessels had likely been in the Abyss for ages and never able to escape, so reproduction continued until one eventually did. But if it were the other option, likely the Pale King yeeted them all down there to have it go down like Thunderdome, the less I imagine about the White Lady’s suffering in both contexts the better.