The so-called Dream God Kingdom of the Alliance of Gods was actually very simple.
In fact, it was the dream summoning divine technique of the Great Xia Incense God. Ji Xiaoxiao had slightly modified it and used the divine domain of the gods as a 'server' to construct a long-lasting dream divine domain.
The divine domains of these 'illegal' gods usually did not do much other than store things. They did not have many believers, and even if they did, their main faith was not them. After death, they might not go to their divine domain. Or rather, except for some slightly important people, such as those whose faith purity had reached the level of saints, most intelligent creatures would only enter the divine domain of the Death Goddess after death.
The so-called Underworld was actually the Death Goddess 'divine domain. It was the final destination of all the dead on the Mother Earth Continent.