Deader than Dead by H.L. Day is a supernatural thriller that grips readers from the first line, delivering a fierce combination of suspense, humor, and a well-executed plot twist that invigorates the genre. This expansive narrative explores the intriguing premise of a protagonist who, quite literally, cannot die. The book is a Cimmerian dive into the existential whilst also balancing the scales with wit and a light-heartedness that is rare in tales involving such macabre elements.

The protagonist of Deader than Dead, named Jamie, discovers his unique affliction after what should have been a fatal accident. Instead of leading him to the afterlife, the accident awakens in him the bewildering awareness of his immortality. The journey that follows is as much about navigating this newfound ability as it is about uncovering why Jamie has been burdened—or perhaps gifted—with it. H.L. Day's choice of a character who is impervious to death raises compelling philosophical questions, interlacing the supernatural elements with a deep, existential questioning of mortality, purpose, and isolation.

Day's narrative style is engaging, rich with sharp dialogue and a pace that keeps the reader turning pages. The exploration of being "deader than dead," as the book's title articulates, unfolds through a series of gripping adventures that push Jamie to the brink of what we might consider human experience. With each chapter, Jamie's character evolves, drawing the reader deeper into his psyche, which is wrought with the innate human fears of loneliness and the unknown, despite his unending existence.

One of the standout features of Day's writing is his ability to sketch memorable, multi-dimensional secondary characters who add depth and humor to the narrative. Whether it's the enigmatic necromancer who provides more questions than answers or Jamie's old friend who tries to offer some semblance of normalcy in an otherwise tumultuous existence, each character complements the story's rich thematic tapestry. Their interactions with Jamie are fraught with comedic relief and poignant moments, creating a contrast that is as stark as it is entertaining.

A significant portion of the book is devoted to Jamie's quest to uncover the origins of his immortality. This journey, paved with ancient myths, modern-day allegories, and supernatural elements, does an excellent job of world-building—a complex structure that holds the many plot twists and characters in place. The incorporation of various mythologies and the supernatural element of necromancy enrich the story, providing a fascinating glance at the intersection between the old world mythic tales and contemporary supernatural fiction.

Moreover, H.L. Day's treatment of themes such as isolation in immortality offers a raw and often poignant look at the paradox of living forever. The burden of immortality brings with it a unique kind of solitude and dispossession; Jamie's character is portrayed in a way that his endless days become as much a reflection on his past lives as a prediction of the loneliness to come. The psychological depth explored in Jamie provides a counter-narrative to the glorified versions of immortality often depicted in popular culture.

From a literary perspective, Day's prose is clean and articulate. There are occasional lapses into over-elaboration, particularly in the middle sections where the pacing might feel sluggish due to the extensive character introspection and detailed settings. However, these are minor foibles in a narrative that is overwhelmingly compelling and well-structured. The language is accessible, yet rich enough to satisfy those who appreciate a more lyrical approach to genre literature.

The climax of Deader than Dead is both unexpected and satisfying, tying up the myriad threads of Jamie’s quest in a conclusion that is both inventive and thought-provoking. The final resolution of Jamie's immortality offers a fresh perspective on life and death, leaving readers with lingering thoughts about the value and meaning of each.

In conclusion, Deader than Dead by H.L. Day is a riveting exploration of immortality that combines dark themes with light-hearted moments. Day’s capability to delve deep into the philosophical while maintaining an engaging plot is commendable. This book is recommended for readers who appreciate the supernatural genre but are looking for something that delivers both an adrenaline-packed narrative and a profound message about the essence of life and death.