Hierro (Ironside) by Holly Black is frequently described by readers as a dark, gritty, and fast-paced conclusion to The Modern Faerie Tales trilogy. Many fans consider it the best in the series, highlighting the romantic tension and the high-stakes, riddle-like quests that Kaye and Roiben must endure.
If you are looking to download the ebook, I can help you find official sources. To better assist, are you interested in: The (Hierro)? The original English version (Ironside)? Other works in the Modern Faerie Tales series? Reviews with content warning for Drug use - Hierro
Highly recommended for fans of The Folk of the Air (The Cruel Prince) series who want to explore the darker, earlier works of Holly Black. What Readers Say
“i love tfota and the elfhame universe, but i so badly want her to write more of this! kaye and corny are my favs, and it was cool to see characters from valiant!” The StoryGraph
While it can be read as a standalone, readers strongly recommend reading Tithe (book 1) first to understand the backstory.
“As usual, Holly Black doesn't shy away from the dark edges, never goes all mushy and creates a fantasy world that is grounded in the realism of her characters.” The StoryGraph