The Divine Gate

The Divine Gate is a barrier that prevents the gods of Eserine, both good and evil, from physically crossing into the Prime Material Plane. The more powerful a supernatural creature is, the harder it is for the creature to pass through the Divine Gate. It is permeable to lesser supernatural creatures and to mortals who have the magic to travel between planes.
Put into place after the Battle at Khisfire. The Day of Retribution, by the Watchers Gretchen  and the Blacksmith.
The Gate was made by the two The Watchers  to prevent the effects of the Gods from actively affecting the lives of mortals.