I highly recommend The Iron Knight. 
 ***** 
 IMMEASURABLE. 
 The Iron Knight left me in awe. Ash was bared like you've never seen him before: indecisive, faltering, broken. But the resilience of his character and the relentless pursuit of his happiness ultimately marked this finale as one of the most satisfying fey series EVER. I uber-love the Epilogue - it was so full of wonder, victory, and possibilities. Julie Kagawa, thank you for dedicating this book to Team Ash. I, for one, was moved. I thought I knew my Winter Prince; guess I was wrong. But how i revel at my mistake! 
 Ash (together with Puck, Grimalkin and two other surprising companions) went out to seek a soul so he can be with Meghan (now, the Iron Queen). What started out as a quest for true love turned out to be an eye opener for the former son of Mab. He was ridiculed for wanting a soul to become human. Does he even know what it's like to become one? No. But his vow to find Meghan ties his essence; breaking it would mean death. Uhh... did Meghan changed him? because I could not see the Unseelie Prince anywhere in this book (okay, maybe once). His character was developed as though he was human already. I'm not ranting - just sayin' that there are times that i found Ash unfaithful to Meghan, and thought that he was only bound by duty and the promise he made, not by his love for the Iron Queen. Oh well, i still love him. And i will say that nothing compares to what Ash went through. NOTHING. 
 I love Puck's flippancy contrasting Ash's grimness. I hate Grimalkin in this book, though. I will grudgingly admit that i love the 'dog' far more than the 'cat'. First half was one amazing adventure after another, i could not almost keep up! Second half was sorrowful but understanding and peace came in the end. It was very, very nice. 
 The Iron Knight is on a somber note compared to the first 3 books. There are times i felt helpless and defenseless like Ash. But when Kagawa wove her magic to wrap up the ending, it was exactly as i wanted it! *sigh* So which love is greater: Meghan's or Ash's? After reading this book, I'd say...Ash's.