First time I've run a good Season 8 module in a while. Loved the story line, could have been a little better worded for descriptions of the areas of the House of Vith'tyl for when the infiltrator went inside, as it was harder to describe the area by extracting informaiton from the DM's descriptions. The latter part of the module involving the ceremonial pool proved to be a good challenge to my players who normally solve puzzles very quickly. The only recommendation I have for the puzzle is that they found it hard to understand what parts of the puzzle went where, a clearer idea or method of showing the players what they need to accomplish could help a lot. I found the stat blocks to be very well made, I'd suggest having the helltouched warlocks have their helltouched features that were presented earlier in the module right in their stat block for ease and less referencing.
Currently my favourite module to run!
[4 of 5 Stars!]