Dan Yami
Wall of Flesh
when Calamity is installed the Empress Den is moved to the right, you can still fight her if you play with Calamity.Hello, I read that the Empress Den spawns directly below the desert. And since appearently the only way to spawn Araneas, you can't fight him on a world generated with enabled Calamity mod as well, because that biome is getting overlapped by Sunken Sea. I think that the biome should be generated somewhere else, or maybe a bit deeper, so it's under the Sunken Sea? Because I saw the boss, it looks dope as heck, but I can't fight him even if I spawn him with other means, since he kills you when outside the Den (at least, that's what I'm assuming).
Just make sure to NEVER enter a world with modded content without the corresponding mod, or else you lose stuff such as walls, which are essentially the core part of the biome.