Many regions and beliefs see Achiël as an important god, but still, only one of many.
The people of Dorwin, however, believe in only one god: The One. The One shares many aspects of Achiel, and is believed to have split off of Achiel worship in the distant past.
As there is One divine, there is one personification of them in the mortal realm: the Supreme Pontiff of the One.
Who the Pontiff is, is not known. It is also considered not important; by their will, wars are started, crusades are launched and heretics punished.