It is a good supplament for Shandow of the Demon Lord, and it adds a lot of player options, world building, and flavor. I am not quite sure who it is for, though. It has some world build stuff that I would want to keep out of world knowledge for the players if I GM (like enemy STATS), but it also has a lot of player options that I would like to as a player. Having it it in the same suplament makes less sense because it is kind of directed to both at the same time which means there is a section in it that is largely useless for both.

Tombs of Desolation is very much like the Demon Lord's Companion on a slightly smaller scale. There are player options and GM tools, and they are modular and can be connected to what you already have in the core rules. However, unlike the Demon Lord's Companion, this also moves the setting into a new area that was only touched on a little in the setting material in the main book.

You can totally use these options with the base book, but they make the most sense when pairted with the new setting details in this book.

The setting is a very harsh, nasty, magically bad desert. You have two undead player races, and a race elementally attuned to the harsh, heated wasteland. In some ways, this takes the oppressive feeling of the core story and takes it up a notch. If the core setting is dark and oppressive, slowly sapping life and vitality from people, the Desolation burns all hope out of you while it drives you insane.

Really a nice addition both to the game's setting and mechanics.

This supplement is fantastic! It introduces interesting but problematic elements that fill a much needed niche in the game.

First off the new Ancestries are tricky advanced things. But mechanically easy to use. The Revenant is a semi-ancestry that can be pluged into any moral human/dwarf one allowing them to turn into an undead soul bound to the living world. It allows players to enjoy an undead hero with out being harmful to the party (directly) and there are heroic and unheroic play options in your backstory explaining HOW you came back to life.

Salamanders are a dangerous bound elemental spirit but can still be heroic if destructive. Just don't try to grapple one.

Vampires are AWESOME...but have a few issues. They are Vampires. Sunlight hurts them, they gain a bane from their magical phobia, and well they need BLOOD to live. It's a very corrupt/insane path and if you are playing a Vampire PC you'll be inching your way into full corruption in short order. However if you want to play a Vampire looking for redemption or a cure it's viable and offered. Just keep in mind the whole group will have to adapt to you inhuman needs.

The new spells are useful and fun. Blood magic is corrupt but it's utility functions can be helpful even benign, but it's origin from Vampire casters and the majority of it being based around well KILLing, it has issues. The rest of the magic fits the theme nicely and hey Necromancy finally get the spell to turn yourself into a Lich! (or Liche)

Then the second chapter is a delightful grab bag of desolation/desert locals that can be adapted for any game. I know I want to send my players to the Vanishing City! The weather rules are harsh but I feel they are missing the bitter COLD of desert live. But the desolation is more in like with Muldor than a true desert so I guess it fits. Great atmospheric stuff to throw at players.

The adventure ideas are a good mix if light on details More adventure seeds. The 4 new relics a mix of vampire and undead.

Most of the monsters are awesome. Just keep in mind the majority are higher diffculity. More boss or massive group battle material. But all are delightfully dark and dangerous. I guess I just wish there was a Demon Lord Bestiary of nightmarish monsters and demons to play with.

Round the supplement out is the Into The Wastelands/The Harrower's Tomb wish reads like a classic fight the undead lord of the land adventure. It's a Master tier character one so ya.

The Desolation/Wasteland adventure seems geared for higher level play in mind but has enough crunch and fluff for lower tier characters to enjoy. Just keep in mind the setting is HARSH and should be killing PCs and NPCs like a Dark Sun convention.