From publisher blurb:
Deep beneath the sun-bathed surface of Everglow lies terrible truths and unknowable realities. Creatures both fair and foul clash, competing for domination at the behest of masters that barely acknowledge they exist, when rarely they do at all. Locked in generational defense of the upper world that has long forgotten them, the deep elves wage a seemingly hopeless war without end. Guarding treasures best left alone, sphinxes prowl the darkness, eyes gleaming and ready to learn despite the misery around them.
Enter a world of horror and beauty, where life is always lived dancing on the finest of wires, as able to support you, or cut you, with equal efficiency.
With content for PF1, PF2, and DnD5, The Depths of Everglow will add to your game whether you plunge into the darkness or bring a bit of it up to the surface with new monsters, magic spells, backgrounds, feats, items, materials, class options and so much more!