A unique world building concept will get me every time. Unfortunately I can't discuss my favorite element of the story, because spoilers, but Lu is able to pair a detailed SF world with themes of weaponization. At the beginning, the SF touches seem subtle, but Lu builds them on top of a foundation of a fractured world. A world with refugees fleeing from their life from colonialism. In the middle of a war, where Talin has been turned into a deadly fighter Lu discusses the ways people are turned into weapons.
In Skyhunter, Talin is mute and has to sign for a large portion of the book. I cannot speak to the accuracy of the representation. Most of the people around her seem to understand her signs (because they need it also for combat), but there are situations where her that is not the case.
Lu presents a world and situations where her characters must contemplate whether we are defined by our monstrous actions. Are we able to be guilty while still being defined by our present choices? Is mercy ever the wrong answer? Throughout Skyhunter we are asked how we become callous, cruel, and merciful. It also illustrates the lengths to which people will go to in order to stay safe. What we will do for what is right, especially when it is hard.