The Storm Beneath The World is the first book in the grimdark duology Children of Corruption, written by Michael R. Fletcher. A really unique novel, which shines in many aspects, the kind of deranged madness that only Fletcher's mind can produce, wildly imaginative, and with an incredibly engaging plot, dark but also powerful.

The ashkaro, insectile creatures, live in flying islands travelling the River of Days; divided in queendoms, following a caste system that is based on the colours of the carapace, equaling the more colourful to the highest caste (which is reflected by your number of names), in a matriarchal immobile system, swapping the classic gender roles. In this context, war is inevitable between Nysh's queendom, which embraces until certain point the ideas of independence from the swarm, and Yil's, servants of the Old Goddess, which is expanding by conquest. 
To prepare for the imminent war, young ashkaro that manifest dangerous Talents, who would be ostracised in other circumstances, are sent to secret schools to be trained as assassins as spy, separated by castes.

Our story follows several of those young ashkaro, from a wide range of castes; all of them manifests Talents, a really original magic system, which also includes an interesting way of balancing the power, with the user slowly walking towards its own madness by addiction to use it. With a short space of the novel, we are totally invested in said characters, sharing their struggles and their own set of problems (and let me tell you, Joh's point of view is simply a marvel, snarky, full of humour, but also presenting the problems of coming from the lowest class of ashkaro's society).
With the advancing of the plot, our characters continue growing in their own ways, not always in totally positive ways, creating a captivating but also horrifying experience, as they slowly reveal their secrets and get lured into using more of their powers; all until Queen Yil moves her pieces and attacks the schools, a situation that will allow our lower-class characters to shine, fighting back against.

Excellently paced, I devoured this novel; there's not a single dull moment, keeping you hooked and making you jump in the chair at many points, with many impactful scenes. As said, you can guess through Fletcher's worldbuilding a layer of social commentary, swapping the roles at many points in clever ways; and it is also worth to mention the details lifted from our own world's insects and invertebrate.

The Storm Beneath the World is simply a superb Grimdark novel, breaking and imaginative; you will absolutely love it if the genre is your thing. And with that ending, I can't wait until we have the second book in the Children of Corruption series.