What, might one ask, is the purpose of a setting book?

In my time playing 2e and 3e, the answer seemed to be details. You could get a book on Greyhawk that drilled into a district of the eponymous city, listing specific shops by name and giving the name/race/class/level of the shopkeepers within, giving an exact roster of precisely how many guards are available at each watchtower. Incredible specifics, but generally organized as a gazette, or even as a census of whatever city was being covered.

That is not what Dread Metrol does.

In 5th edition, much of the setting information is about atmosphere. Some major NPCs might be given some information, but in many cases the guidance is often an idea rather than the specific numbers. This is how Dread Metrol is organized; of the major figures in the city, only Queen Dannel herself gets a statblock, and the specific numbers are generally vague - apart from the calculus of how many people the Ghallanda heirs have the power to feed.

Speaking as a DM, I find that specific answers in a setting book are only useful if the players are asking that specific question - and even then, it takes time to look up and reference to make sure the answer is for the correct building. Specific information for specific locales means that if the party chooses to ignore those locales, a new answer must be invented anyway - which, in turn, means that I find the 5th edition approach more useful.

This, in my opinion, is where Dread Metrol shines with terrific lightning fueling dread artifice.

In thirty-six pages, the beseiged city of Metrol is explored - not in exhaustive specific detail, but in laying out the major factions at play. In true Eberron fashion, the availability of magic is explored - for instance, magic does exist to create food ex nihilo, and the city is making full use of those resources. It's just that those resources aren't enough, forcing them to turn to...less savoury options. The Queen is given full characterization, and the powers around her are explored.

But little here is an absolute truth. There is a secret to Ghallanda's ragout - but the DM is given a list of options for the secret, and invited to use whichever best fits the adventure they want to tell. High-ranking rebels are not listed explicitly, but there are sets of names and personalities and secrets - again, inviting the DM to mix-and-match whatever amuses them best. There is inspiration here, but no two Dread Metrols will be exactly alike.

It's evocative. The art pieces convey the tone very well, and a dismal tone it is - undead, starvation, experimentation, ruthlessness, an entire city of atrocities and desperate survival. The brief domain writeup gives the faintest sense, but the much-appreciated content warnings outline just how horrifying a place this is.

(And, one might note with amusement, the darkness Dannel descended to in a mere four years compared to the likes of Strahd or Drakov. The Queen has rapidly earned the title of Darklord.)

This is, bluntly, what I would look for in an Eberron horror setting book. It gives endless ideas of atrocity - not all of which I must use, but some of which might invite themselves to the Eberron setting at large. If this is how we see the Houses sinking in desperation and isolation, what might the larger part of the House be hiding? What tools of war are implied here that might yet be found in the wake of Thronehold?

And then, if that alone weren't enough, it explores options for players from this Domain. The writers have even included a player's version of the setting, trimmed down to keep the DM's secrets behind the screen, but informing them of just how terrible the dark side of Eberron can become. This is an asset to me - a document I can show my players to let them consider the themes, while keeping many of my true plans hidden.

And, of course, there is an adventure. I have yet to run it, but I appreciate how much choice it offers. There isn't a single solution to a problem, there's several - all with dire consequences attached. NPCs are important, but the information they hold can reach the party by other means if the dice roll disaster. There's no one true right answer - merely the price the Unbroken ask in exchange for offering the party the help they need. It's a great way to explore the morality of the PCs, and what lines they will and will not cross in their own desperation. The new monsters fit the adventure's tone and the setting perfectly - atrocities that, in any kind of just world, would not exist.

In conclusion: This is a dark setting. It explores horror in many aspects, and I would argue it might surpass the body horror of Lamordia and the war atrocities of Falkovnia. Some groups may wish to avoid it for those reasons, which is understandable - but for groups that want to explore the compromise of morals when faced with a desperate situation, this is a fantastic exploration of that terrific theme. The Dungeon Master is given the freedom to pick and choose which specific themes and secrets they want to explore, but the tone is well-presented.

This is the dark side of Eberron, and precisely what I hoped for from a setting book.