The Stranger pretty much just gets lip service. He is mentioned in the texts occasionally and always seems to have some secret plan of his own going on. He will show up and ask for things form the other two gods and go off on his own without any records being left of what he does with what he asks for. The dwarven creation story is a good example of this.
Most are not aware but there is a sect of women who worship the stranger but their rites are not known by the common populace nor is it known if they are actually getting divine powers from the stranger or not. They are kinda a fringe religious organization. Many believe that they are just a tale to scare children or give conspiracy theorists something to talk about.