"Sound (Solid, #3)" by Shelley Workinger
Quoted on back cover:
"If there is one series that I wish more readers knew about, this is it."
"Deity (Covenant, #3)" by Jennifer L. Armentrout
Quoted inside of the book:
"5 of 5 stars. I've never read a book that screwed with my emotions as much... Deity made me want to throw my book across the room numerous times, and to me, that just shows how great Armentrout is at her craft. Because when a reader is that invested in characters from a book, the author has clearly done something right."