Levels of power

There is a hierarchy of relative power among the forces and creatures of the world. Note that the lines are blurred in most cases; a particularly powerful extraplanar creature may rival a deity in power, for example.

1. Contract magic: Whatever entity or force causes contract magic to work is sufficiently powerful to directly affect deities. It is the only known force to be able to directly subvert divine will, and there are no known powers above its dictates.
2. Deities and Artifacts: The divines and their most pivotal treasures comprise this level.
   • Major deities or full pantheons of middle deities in concert
   • Minor deities, extremely powerful servitors of major deities, or major artifacts
   • Minor artifacts; primordials.
3. Extraplanar creatures, magic, and mortals: This tier is a wider spread and somewhat looser, but generally follows these guidelines:
   • Most fey, demons, devils, elementals, celestials
   • Mortals that manage to cast off their mortality in some way
   • High priests of powerful deities, elders of the druid path, devout monks, great kings and generals
   • Mortals with the aid of a powerful patron
   • Magic items below artifact-level (generally created by others in this tier)
   Competition is fierce and death doled out cheaply, as many seek greater power or try to keep what power they have.
4. Everyone else: Anyone not named above probably fits here. Many seek to climb in one way or another, but most of mere common folk are happy enough with (or only suited for) their lot.

Most entities struggle to have a lasting effect on tiers above themselves without engaging a higher tier or the cooperation of their peers.
It's also notable that aberrations and other creatures considered "outside of nature" can theoretically exist in any tier.