I'm going to write the same review for Volumes 1 -3 which form the first story arc for this series.

I have to admit I picked up and set back down Vaughan's work a few times this year, despite its popularity and even though it was on my Recommended Reads list for graphic novels.  I'm not a fan of high fantasy or non-scientific science fiction, and this seemed both, plus an audacious effort to shock readers with sexually provocative imagery. And then I read it.

The larger, and by far, most interesting story is that of two people from different warring factions wanting to raise their child in peace. New parent anxiety, doubting in-laws, and the like are all here--even a street-smart teen babysitter (probably the highlight of the entire work so far). The parents speak and lust frankly, and what most books and films will tidily erase from domestic child-rearing stories is here put front and center. Surprising, but genuine.

That said, there is nothing genuine or believable about the carnival/bacchanale universe Vaughan has assembled around them.  Nothing here is human and the variety of critters is so vast that readers can expect literally anything at all to walk onto the page--and often does, hunting down our new family.

The problem for me is what Vaughan has retained as "human-centered" around all of this universe: almost everything is human-like in its sentience, means of communication, and fundamental form (a human but also a spider, a human but a great big baby, a human but with wings). This permits Vaughan to build romances between them all with abandon, and it allows him to make spectacle of the more retching biologies of all. In other words, the universe is created for a storyline to offer extraordinary graphic imagery and what I have to identify as fetishlike sexuality. This isn't a universe built for anything at all except to see what oddities might . . . collide. A pretty thin disguise.

I could spend a great deal of time describing the political, psychological, and ethical problematics of such writing, but I will save it on this forum and say only that this is definitely an adult series of graphic novels, and not a series for all adults, at that.

If a reader can set aside their own distaste for their own idea of the obscene (and trust me, there will be something for everyone), they will be gratified at least that Vaughan has offered a real and refreshing story that I, at least, will continue to read.