Nyx is impossible to defeat. That's why there needed to be a Seal in place so the desire to die from all of humankind could never touch her once more. Those malevolent feelings became one super being called Erebus... He's the reason Orpheus still suffers. All Erebus wants is to break Orpheus and get to Nyx. So if there's a Nyx about the Mall... Erebus tries harder to get through.