What an AP! I'd enjoyed this one as a player through to book 3. As a DM running it several years later, my group is having a great time. Its taken 19 sessions (yes..19) to reach the end of book 1 but we've really made the city come alive with details of NPCs and side adventures to make Kintargo feel real.
I took several of the other DM's advice in modifying the Many Steps Monastery, specifically to its gate-keeper Yilliv. In a DM 'fudge', I allowed the lessor planar binding to be subject to a dispel magic. Keeping his telepathy and other motivations intact, it allowed the players at least a chance to overcome a challenge which should've allowed a different 'out' rather than just combat.
The party identified the spell being used on Yilliv, then used the dispel magic scroll found on Raul to successfully dispel the magic binding (Nat 20 roll which led to cheers at the table).
The group is now sneaking about the Monastery with the plans of taking out the monks one at a time before dealing with Nox. Knowing players...this plan will last about 5 mins into the next session. But, I have high hopes they will encounter the finale on their terms.
The group almost got crushed upstairs by Raul and his monks and consists of two new players, one veteran, and a NPC PC. One player commissioned artwork of the group already. I'm hoping Nox doesn't ruin the plans of a party portrait this coming session.