I don't know if I could commit to doing this, because I don't feel engulfed in the universe enough anymore, but suppose you do in fact have your characters be sitting in the power vacuum and you have the Outsider playing with the situation by granting gifts and bone charms to people on different sides of the struggle?

Or maybe there's an energy crisis, since whale oil hardly seems like a renewable resource when there demand is so high. So you have the Outsider playing some role in helping the characters traverse the slowly unpowering and dying city of Dunwall, aiding someone to seek or seeking some other power source.

In other words, the Outsider should be a central provocation.