Forsaken Souls: Fourth Novel in the Callum Walker Series

by J.M. Shaw

Driven south by their brethren in the Northern Kingdom, the Der'geron have bided their time for nearly two centuries, nursing hatred and plotting vengeance since their defeat in the great elven war. As a new conflict draws ever closer, Queen Jobella struggles to assert her authority over her northern domain—battling civil unrest, sabotage, and misinformation while attempting to mend fractured alliances.

Meanwhile, Callum and Jax set out on a perilous journey to repair the veil separating the magical realm from the human world. Unbeknownst to them, their path leads directly into the heart of danger, where they are captured by the Der’geron. Imprisoned in the hellish grotto beneath the subterranean city of Elfarian, Callum and Jax are forced to work or die at their enemy's command.

However, danger turns to horror when Callum learns of the Der’geron King’s plans for the Northern Kingdom and the rest of the realm. What is to come will be a reckoning, not a war. It will be a battle for the ages, where both lives and souls are at stake, and death is not the worst outcome.

Imperilled by violence, assailed by evil energy, and tempted by dark magic, Callum must stand against the rising darkness, but first, he needs to find the strength to face his buried anguish, even at the risk of fracturing what remains of his sanity. Yet, there is hope for a happy ending, if only Callum can summon the courage to accept it.

472 pages, Paperback

Published June 1, 2025

About the author

J. M. Shaw is an award-winning Canadian author who lives in Alberta with her husband and two young children. She’s been writing since childhood, building worlds from raw imagination and quiet observation, but it took years before she found the courage to share them. For Shaw, storytelling has always been more than a hobby; it’s a passion.

In 2019, Shaw was diagnosed with autism and ADHD, a turning point that brought clarity to a lifetime of feeling “too much” or “too different.” Her intense focus, emotional depth, and ability to live inside fictional worlds became not flaws but the superpowers of a neurodivergent mind. These qualities shape her stories, infusing them with realism, heart, and meaning, and giving her the courage to finally share her creative works. Her worlds may be fantastical, but her characters—flawed, searching, and deeply human—resonate on a personal level.

When she’s not writing, Shaw enjoys connecting with nature, curling up with a good book, and dreaming up new worlds. She also finds joy in encouraging young writers to pursue their own passions.

Reviews

[Adam]

I love this series. The ongoing adventures, and the maturing of Callum as a warlock keeps each book fresh. Looking forward to the next chapter! Hopefully it comes out soon!

[Melina Lobo]

Forsaken Souls is the fourth book in the Callum Walker series by J.M. Shaw. Since I haven’t read the first three books, this review is based solely on this installment, though I understand it’s a continuation of an ongoing story.

The book has a dark tone that works well for any fantasy lover, immersing us in a magical world filled with conflict and drama. Callum and Jax are clearly the central focus, and despite this being part of a series, the author delivers an engaging plot that leaves you wanting more.

That said, at over 400 pages, there were moments where the pacing dragged. Some characters felt unnecessary or a bit one-dimensional.

Still, the worldbuilding was a major strength. I truly felt like I was part of the journey. I’m looking forward to book five as I enjoyed the author’s writing style and want to see where the story goes next.

[Randi-Lee Bowslaugh]

Being the fourth in the series, this book easily picked up where the previous installment left off. There was no lengthy rehashing of events, which allowed me to jump right back into the story and reconnect with the characters almost immediately.

The relationships between the characters continue to evolve, and it's interesting to watch them grow and change throughout the story. As always, the dialogue was a particular highlight for me. Conversations felt natural and engaging, helping to deepen both the characters and their connections to one another.

I really liked that the main characters don't magically know all the answers; they had to actively seek out information, make mistakes, and work through obstacles. It made the story feel more believable and kept me invested in their journey. Especially how it integrated mental health themes. These elements were woven into the narrative in a very natural way; they never felt forced or overly emphasized but instead became part of the characters' lived experiences, which adds realism.

The readers are introduced to new characters, new forms of magic, and fresh struggles for the protagonists. The change of scenery was refreshing, and I enjoyed learning more about the realm's history. Expanding the world added another layer of intrigue and made me eager to discover what comes next.

If you are looking for a fun fantasy, with a growing world and deep characters, this is the book for you.

[Dani Urban]

Forsaken by J.M. Shaw is the fourth fantastic installment tho the Callum Walker Novel series. J.M. Shaw's latest book in this sci-fi series is dark, psychological, and explores the weight of power. Power comes at a cost and if not used right is just utter destruction. Here, I followed Callum Walker as he's been captured and is struggling to survive the torments both psychologically and physically. Work or die made me think of prison camps when they forced prisoners to work if they couldn't work, they'd die. It also almost has a Holocaust die or work till death kind of vibe. Horrifying, suspenseful, and thrilling. Callum finds temptation at the worst possible time when he's broken and at his all-time weakest. He has a two choices and either choice has catastrophic endings. High risks, deadly scenarios, end of the world kind of thing, and trauma peaked with tensions. The tensions are not just the fighting enemies but the fighting of one's mind when barely surviving in a horrible outcome without any hope. Callum Walker is tested unlike any character I've meant. I was not sure which way he would have tilted until he did. Warfare has a way of recking one's psychological and mental health. No one is ever the same again just as Callum changes. Overall, J.M. Shaw shows readers the gruesome parts of political warfares and their lingering presence on those who it destroys. What a dark epic read...

I received this copy from the publisher. This is my voluntary review.

[Anthony]

The Review

This was such a gripping and memorable entry into the Callum Walker series. The mesh of world-building and expansion upon the mythos of this magical world was perfectly executed, allowing the reader to fall deeper and deeper into the world the author has created. The conflict the story explores between the Northern Kingdom and the Der’geron, and the dark magic's impact on those attempting to wield it, are perfectly captured and elevate the action significantly as the story progresses.

This story's most significant impact is through the character progression, especially for the protagonist Callum Walker. Between his relationship with his brother Jax, the new allies he makes, and his struggle with past trauma, the readers form an emotional and heartfelt connection with this character, one that keeps the reader engaged thoroughly throughout the story.

The Verdict

Entertaining, thrilling, and haunting in its delivery, author J.M. Shaw’s “Forsaken Souls” is a must-read dark fantasy and genre fiction read with hints of horror and magical realism at the same time. The twists and turns this story takes and the story elements that end with an open-ended note leave a promising and hopeful note for the future of Callum Walker and the character’s series moving forward.

[Readers Choice]

Forsaken Souls, penned by J.M. Shaw, is the fourth installment in the Callum Walker series. Since their defeat in the great elven war, the Der’geron have been plotting vengeance. Captain Arvek Vacan, in particular, yearns for the chance to avenge his kin’s centuries-old humiliation at the hands of their northern neighbors.

During a brutal capture, one of the captives defiantly declares, “Callum Walker will hear of this atrocity and avenge us!” Soon, Callum and Jax embark on a perilous quest to restore the veil that separates the magical realm from the human world. While Jax finds love with Tess, Callum still struggles to understand what love truly means. Will he find anyone?

The story intensifies when the Der’geron seize Callum and Jax, revealing the dark ambitions of the Der’geron king. Faced with overwhelming challenges, Callum must decide how far he is willing to go to protect both worlds.

Packed with action, unexpected twists, and emotional depth, Forsaken Souls is a gripping tale of war, vengeance, and destiny. Readers who enjoy stories of conflict, courage, and the eternal struggle between good and evil will find this an engaging and thrilling read.