Captain Kurtiz:
Those creatures grew stronger there and whenever the gates opened, they were able to go to the places they wanted.
However, when the Seal of Punishment was released, it affected multiple dimensions. A lot of things were changed because of that impact, and even Nightmare Kamaloka was affected. I'm not sure about the details, but the various paths to Nightmare Kamaloka stopped working.
The problem is that the dimensional door is linked to a place near Aden.