To be honest, it's really just 1 star. From Dungeon Born to Dungeon Madness to Dungeon Calamity, you get a feel of the books with respect to their names. Dungeon Born was when Cal was born. Dungeon Madness was when Cal created that zombie bacteria and Cal became 'mad' when Dani was stolen. Dungeon Calamity was when Cal went on a rampage. The way I see it, the title gives an idea of what's going on in the current book and possibly the next book.
Dungeon Desolation... 'Desolation' is defined as 'a state of complete emptiness or destruction.' Combine that with Dungeon, you get either no more dungeons or the destruction of dungeons. Dungeon Desolation was basically nothing about 'Dungeon Desolation'. This title is now 100% referring to Book 5.
I listened to this book as an Audio Book narrated by Vikas Adam. He's an amazing narrator and I did enjoy his performance again. I had to give this book 1 star for Vikas' performance. One minor thing was 'Acme' (pardon my spelling as I can't spell from just listening acne -> acme). 'Acme' is supposedly the law that governs all laws and at the top of the tower. His voice or the representation of his voice in Book 3 and 4 changed.
Book 3, Acme was personified as 'I'm too cool for you kids'. Book 4, Acme was personified as annoying overreacting school girl that always go "Omg, omg, omg, I chipped a nail".
All that aside, on to the actual book now. To keep it short, Dungeon Desolation has way too many bad/overused tropes and the whole book is bad.
I don't know why but all the characters feel shallow/hollow and lacking. There's not enough screen time either. Like Dale's crew, they aren't even secondary characters in this book. They're like recurring side/minor characters. Dani's role plummet to housewife. The council basically disappeared. Chandra could've had a good role in exploring the laws, tiers and stuff but it was half-assed and abandoned.
The author opened up so many different paths the book can go or ideas to explore but he just left them at that. These paths don't mean anything if they are left as is and they would simply waste screen time. There's no concrete path or goal of this book. I was under the impression Cal would reclaim town by town, city by city, dungeon by dungeon, node by node until he's strong enough for the finale. That didn't happen. Cal and Dale did a bunch of randomness and then jumped to the final battle.
There are a ton of tropes. For example, a big bad jerk comes in and take over. The two that always bicker and hate each other ended up together. Random heroic death that is totally unnecessary but was included to make it heroic. The protagonist is randomly the root of all problems. The world loses all mana. Forced to do the bidding of a 'bad guy'. Over the top power spikes.
And I swear there are inconsistency with the whole cultivation techniques and whatnot. Random exceptions or 'new' methods tossed in just to make the protagonist's power level go up up up. At the end of Book 3, Dale was a D rank adventurer and Cal was a B rank dungeon. And they struggled really hard through 3 books to get there. In Book 4? They both jumped a rank and the amount of effort they put in is the effort to make cup noodles. The author didn't bother writing how they struggled. He just threw in a big bad mini boss and escalated the conflicts. So what do our protagonists need to do? Power boost!
The author literally threw C and D rank adventurers in a S rank battle.
You know how Cal was trying to get free mana? Like to be independent of adventurers? Yeah, it makes little sense. Cal made mana absorbing runes and made them go over all the ley lines and nodes. Here, Cal has unlimited mana. But then, he's bickering about having to kill 2 groups of adventurers to make some mythril armour.
So Cal ends up with unlimited free mana. It's a horrible idea. He has like zero limitation and can easily reach SSS rank, just pump it in. Cal has little to no limitation so things will escalate and get out of hand. Consistency would also be hard to maintain. And that's exactly what we got, randomness and over-the-top.
Like, apparently, the guild is not as good as it was portrayed in the first three books. Rather than subduing a murderer, the guild just offered the murderer to be a guild member and help out while killing all he wants without a care. Oh, the murderer is also a S rank adventurer. He's totally randomly tossed in to push the plot the way the author wanted.
There's more but I'll stop spoiling. One last one, I got no clue how the mana/magic of the world enforces the law, like how Dale owns Mountain Dale and has the ability to tell people to get off it. Baron Dale is no longer Baron Dale as the two kingdom that gave Dale his nobility is 'destroyed'. But at the same time, the prince and princess ascended to the throne already. They also have zero screen time. To keep it short, I don't get this whole concept nor do I agree with the results.
tl;dr version: it's a mess.