That’s a good point. I’'m open to other ideas. I don’t like “vortex” as it sounds too science-fiction for my taste.
I will now share the sad truth that in my very first Auran Empire campaign, 5 years ago, the sinkholes of evil were called “tainted lands”. There were “taint elementals” and “taint demons” and so on. Unfortunately I was not aware that taint has an urban dictionary definition that is at odds with my desired sense of the macabre. Let us say that the atmosphere of bleak evil I sought to create ended every time I mentioned taint anything.