Corrupted Growths.
Achilles knew much about them, and also very little.
Observable Existence was unfathomably grand, but it had no singular caretaker. The inhabitants were the caretakers, THE entities and lesser beings alike contributing to the maintenance of reality through actions both conscious and unconscious. The Corrupted Growths could be considered akin to weeds infecting a garden and trying to destabilize it, corruption that emerged naturally from the tension between order and chaos that permeated all of Existence.
Over eons, THE Entities routinely cleared Corrupted Growths as part of their cultivation...if they had acess to the Seas of Tian. It wasn't hard or taxing as it simply required a bit of exertion of Civilizational Authority, pressure applied to corruption until it dissolved into purity that rejoined the fabric of Existence.
