When the psychic mages of the families in Gloomshade City finally succeeded in expanding the defensive barrier to cover the entire city, the swarm's attack had effectively failed.
Although its ground forces eventually broke through the ratmen's encirclement tactics, by the time the swarm fought its way onto the divided battlefield, its vanguard had already been wiped out in the counterattack launched by the city's forces. Reinforcements from several other cities belonging to the Dabria family also arrived after hours of fierce fighting.
And that wasn't even mentioning the fact that the damn ratmen just wouldn't stop coming!
Black Servant Forest's relentless mobilization caused the ratmen to dig more and more tunnels across the battlefield. In the end, one group of ratmen—whether they'd lost their way or were simply charging too fast, no one knew—actually dug a tunnel all the way to the vicinity of the hive near the eastern exit of the Eternal Rift.
They madly plundered the worker bugs and took them back as "holy communion." They even disrupted the hive's biomass recycling for a time, forcing the hive master to divert some of its soldier bugs to defend the hive.
Under the twofold pressure of the front line in crisis and the rear under attack, this outpost of a mere peripheral hive finally couldn't hold out. At some point, the swarm began to retreat of its own accord. As usual, they took all the biomass from the battlefield with them, to hatch the next batch of soldier bugs and destroy the city before them.
This was a very dangerous sign.
Experience from the Locust Wall showed that if a hive couldn't be destroyed in the first battle, the defenders would be dragged into the swarm's rhythm of warfare and trapped in a vicious cycle of "the more