Setronel was raised in the temple of Calistria in Oppara. He never had any blood family and so he has no family name. He spent his days in reverence and study during childhood. When he became an acceptable age he served the temple as a plaything of noblewomen (and a few noblemen), working as one of the sacred Calistrian Prostitutes.
A small group of the prostitutes at his temple had a game that they liked to play where they would watch passers-by from the windows and find one that they all agreed was attractive. They would wait one night and then attempt to seek out and seduce the selected individual, the first reaching the goal being the winner. An added requirement was to maintain a disguise so as to not embarrass their nobler clients. This game led to Setronel's eventual job of seeking out those who have wronged the church in some way at the clergy's behest so that they might receive appropriate punishment.
Recently, Setronel and most of his fellows who participated in the game have been sent from Oppara. There was little need for the number of them present there and his expertise would be put to much better use elsewhere. He decided that he would see what he could do in Absolom and ended up joining the Pathfinder Society for the travel opportunities it presents.