The Grim Conspiracy

Fear and hate will corrode society. Well-fed, they are hard to suppress before destroying it.
A catastrophe shatters High Priest Ickletor’s devotion to his god. Without ethical constraints, baser instincts prevail among the unscrupulous. In such a circumstance, one might even conspire with Death to achieve ultimate power? What would a god do to escape the Underworld? Unleashed and unrestrained among the world of the living, such a dark god could destroy all life.
Is there anything an unlikely hero could do in the face of such a covenant to save the world?