The King in Crimson
Importance:
Alistair Draven, the old king Ederia is still built around not naming. Lord Cerwyn's journals trace a friendship with him that soured over the years, until Cerwyn decided the world could only be saved by Draven's death. The Church of the Cleansing Tempest exists solely to destroy what remains of him, along with any traitor to the throne it finds along the way.
Since then
There is no throne I would not shatter, no covenant I would not unmake, no god I would not drag screaming from his seat in heaven, all of it, every last stone of it, if that is what it takes to keep them safe.