Once every decade the Deities choose one of their own to become Emperor of the Land. They are chosen depending on how popular they are (how many believers they have, how many prayers they receive, etc). The Emperor is a neutral party whose main purpose is protecting the land and all who live there as well as being a judge between Deities who might sometimes clash for a reason or another.
A Deity cannot be Emperor twice in a row.
The Emperor is given an ancient artifact from the Gods, a magical Crown that gives them unique powers and abilities, for as long as their reign lasts. That Crown takes a personalized appearance depending on the Emperor using it.
Chains down a single Yōkai with a force made entirely of his Will. The Yōkai is thus held down, immobile, sometimes unable to speak.
The same as Will [link] but for a larger area/group of Yōkai. It's much harder to maintain than a single target, though, as it requires constant concentration.
Allow the Emperor to shut down, lock down or open new Permanent Gates [link] at will.