A combat, exploration, and puzzle-oriented adventure that will offer your players the challenge that they are looking for. The final battle is thematic and there are options throughout the adventure for the DM to easily switch through two different challenge modes.
The pregenerated characters have depth and will save you a lot of time if you are planning to run this adventure as a one-shot.
Files with all the maps are included separately so you can either print them or slot them easily into your online games.
I would recommend this adventure to DM's that are looking for inspiration for a Tier 4 or want to send their high-level players literally to Hell to face Tiamat's forces.