So one of my group is pretty excited about Down Darker Trails and wants me to run it next during our weekly Cthulhu game. I was thinking of using The Golden Scorpion from Worlds of Cthulhu however as Nyarlathotep has played some part in our last two campaigns (and potentially a third if we run Sense of the Sleight of Hand Man), I was thinking of changing Nyarlathotep to a different elderitch god. I was wondering if anyone can think of a suggestion which may work or anything that may not work in the campaign?
My first thought is to replace Nyarlathotep with Tsathoggua. Have the Toad God place a geas on them and of course the black stuff which keeps the PCs alive can be some sort of formless spawn. The climax could easily be moved from that canyon to an entrance into N'Kai. Also, I know Yig and Tsathoggua often clash so perhaps that explains why Tsathoggua wants the Scorpion. Using the investigators as pawns in the Toad God's war with the Snake God seems like something the slothful god would do.