Welcome to Everworld, a place that shouldn't exist but does.
The idea of Everworld is that, many years ago (said to be near 1,000 years in Everworld time), the ruling gods of every pantheon (including Zeus, Odin, and Ra) assembled and agreed to abandon this world, known as the Old World, and create a new one called Everworld. Then the gods went across to it, bringing with them every variety of magical creatures, as well as various human worshippers to continue serving them. The barrier between these two worlds was weak for a while, allowing later medieval beings (such as the wizard Merlin) to cross over as well, but by now, is almost closed.
However, there are worlds other than the Old World and Everworld, which are inhabited by alien species unlike anything human or mythological. These species have their own gods, who also crossed over into Everworld. One of these species, the bug-like Hetwans, has a deity called Ka Anor, who, unlike human gods, requires the unusual sacrifice of gods to consume. His servants, meanwhile, behave as religious zealots, following Ka Anor's will to the death. They will fight mortals if they stand between the objective of pleasing their god.
Certain humans have the power to open a gateway between Everworld and other worlds, including a girl named Senna Wales, a powerful and self-serving witch residing in a suburb of Chicago. When the Norse god Loki brings her to Everworld, planning to use her to open a portal so that he (and, he claims, the other gods) can escape back and reclaim the Old World, several people she knows are drawn into Everworld with her, and must find a way to keep both worlds safe from evil forces while trying to find their own way home. Over the course of the series these characters become more and more involved in the conflicts and politics of Everworld's supernatural inhabitants, while Senna hopes to overthrow them all and rule Everworld for herself. [[source]]