Course of Events
In order to maintain such a colossal operation, Vox had required a huge number of creatures to tend to this gigantic cradle of wood; the Undertowners had been unwilling to provide such assistance, and so Vox had unmercifully turned to slavery, having his High Chancellor Amberfuce enlist the services of General Tytugg's Hammerhead and Flat-Head Goblins to round up healthy Undertowners to work against their will on the Forest.
The Goblins, having arrived from the Goblin Nations across the Great Mire Road in twos and threes (so as to not have the Shrykes suspect any underhand dealings), were forced to lay low in Undertown until the signal from Amberfuce upon which to act. Upon instruction, through seven days, workers had been forcibly conscripted, and those too old or unfit to work, "had been slaughtered on the spot", and mass graves dug to lay their carcasses.
This led to a new era of slavery and terrible hardship in Undertown, as Tytugg's Goblins seized control of the city against Vox's will, leaving the 'Most High Academe' virtually powerless and confined to the Palace of Statues. This lead to the Third Great Migration of Undertowners to the newly-founded Free Glades, where slavery was once more forbidden.