The Eternal Ones by Namina Forna is a spellbinding entry into the domain of speculative fiction, where the mastery of prose meets the intrigue of an endlessly imaginative narrative. Forna, already acclaimed for her gripping storytelling in previous works, continues to explore themes of power, destiny, and resilience through a richly crafted world that both enchants and horrifies. This novel, not merely a sequence of events, but a profound journey into the ethos of its characters, offers readers an evocative blend of emotion and adventure.

The story orbits around the audacious Aminata Sissoko, who discovers that she is a reincarnated goddess destined to battle a rising darkness that threatens her world. Forna's choice of Aminata as the protagonist is not just pertinent but pivotal, for Aminata embodies fear, hope, rage, and compassion—emotions that drive the narrative forward. Her character unfolds beautifully and painfully as the plot progresses, illustrating a deeply human story wrapped in the fantastical.

Forna's world-building is meticulous and vivid. The settings span from ethereal realms that almost burst from the pages in a kaleidoscope of colors to stark, shadowy corners of the Earth that are suffused with dread and foreboding. The versatility in the setting is reflective of the novel’s thematic depth, dealing with dualities such as light versus dark and past versus present. Each location in The Eternal Ones is not just a backdrop but a critical narrative element that exemplifies the characters’ internal struggles and their external conflicts.

An important strength of Forna’s writing lies in her ability to weave complex relationships amidst an intricate plot. Relationships in the novel are neither incidental nor merely supportive to the storyline; they are foundational to the characters’ evolution and critical to the narrative's propulsion. Particularly noteworthy is the dynamic between Aminata and her antagonist, whose enigmatic bond blurs the lines between hatred and love, destiny and autonomy. This complexity adds a rich layer of depth to the reading experience, ensuring that the engagement with the characters is both philosophical and emotional.

Strong female characters dominate the canvas of The Eternal Ones, but their portrayal is far from one-dimensional. Forna nuances her characters with flaws and fears, making them relatable and real. Each character’s journey is a testament to Forna’s ability to empathize with the feminine spirit, irrespective of its origin in the mortal or divine realms. These portrayals encourage a contemplation of strength and vulnerability, seen not as opposing traits but as coexisting qualities that define humanity.

The pacing of the book is another element where Forna shows her adeptness. Balancing fast-paced action sequences with slow, introspective moments is no small feat, yet The Eternal Ones manages this with grace. Readers find themselves caught in a relentless flow of events that demand attention but are also allowed moments of quietude where the deeper meanings of these events can be contemplated. This rhythm not only enhances the readability of the novel but also mirrors the chaotic equilibrium of Aminata’s world.

However, while the book scores high on many fronts, it is not without its minor pitfalls. Certain plot twists, though effective, come across as slightly predictable to seasoned readers of the genre. This does little to detract from the overall enjoyment but is noticeable nonetheless. Additionally, the exposition, particularly in the early chapters, may feel dense to some, as a vast amount of information is delivered to set up such a complex world. Patience, however, is richly rewarded as each element becomes crucial as the story unfolds.

In conclusion, The Eternal Ones by Namina Forna is a substantial contribution to the fields of science fiction and fantasy. It stands as a beacon of strong female characterization, complex narrative threading, and intense thematic exploration. Forna not only entertains but also invites readers to question and reflect upon eternal truths through the lens of a reimagined past and a speculative future. For those who appreciate layered storylines and profound character studies within their fantastical narratives, The Eternal Ones is a must-read that promises to deeply satisfy and invariably enchant.