My Eternal Light by Alanea Alder is a celestial tapestry that intricately weaves themes of love, spiritual evolution, and the timeless battles between darkness and light. Set in a universe brimming with celestial beings and otherworldly realms, Alder’s narrative is both ambitious and immersive, inviting readers to explore a universe as vast in its lore as it is in its emotional depth.

The novel introduces us to Seraphina, a young Light Bringer who has been tasked with the seemingly insurmountable challenge of preserving light in a world that is incrementally succumbing to darkness. Alder's character development shines exceptionally in her protagonist. Seraphina, imbued with both naivete and an indomitable spirit, is a beacon of complexity—her journey is not just about the external battle against darkness, but also an internal struggle towards self-discovery and acceptance. Supporting characters, such as the wise yet mysterious Elder Micah and the brooding, dark Bringer named Cain, provide compelling counterpoints to Seraphina’s luminous character, creating a dynamic narrative rife with conflict and contrast.

One of Alder’s most commendable feats in this novel is her world-building. The celestial universe in My Eternal Light is meticulously crafted, with each realm having its own unique properties, history, and connection to the cosmic balance. The description of the Light Realm, in particular, is breathtaking—visions of shimmering towers and ethereal landscapes are juxtaposed against the haunting and shadow-cloaked terrains of the Dark Realm. This detailed setting is not just a backdrop but plays a crucial role in the story, influencing the characters’ actions and growth.

The narrative is well-paced, with a satisfying blend of action, dialogue, and introspection. Alder employs a poetic style that fits the otherworldly theme, with eloquent descriptions and a rhythmic flow that carries the reader through the pages. Particularly striking are the scenes of celestial warfare, where Alder's prose sweeps you into the fray, making you feel every pulse of light and shadow as they clash.

However, while Alder's linguistic flourishes are generally a strength of the book, they can occasionally verge on the overly ornate, which might detract some readers from the core narrative. Additionally, the central romance between Seraphina and Cain, meant to be a poignant exploration of forbidden love, sometimes feels underdeveloped. Their relationship, critical to the plot’s progression, at times relies too heavily on typical genre tropes of star-crossed lovers rather than carving out a unique path for itself.

Thematically, My Eternal Light is robust, navigating through questions of fate versus free will, the nature of good versus evil, and the transformative power of love. The spiritual undercurrents of the story are thought-provoking, inviting readers to reflect on their own beliefs about destiny and the cosmos. It is these themes that elevate the novel from a mere fantasy to a philosophical inquiry wrapped within a celestial saga.

Inclusion and diversity are subtly woven into the fabric of Alder’s universe. The celestial beings, while primarily depicted as ethereal and beyond mortal concerns, display a range of emotions and conflicts that resonate with human experience. Through this, Alder seems to suggest the universality of struggle and the shared quest for enlightenment across all beings, which is a poignant takeaway in today’s global landscape.

From a reader engagement perspective, My Eternal Light stands out for its ability to maintain suspense and intrigue. Each chapter methodically builds on the last, culminating in a climax that is both satisfying and open-ended, suggesting that Seraphina’s journey might continue in future installments. This effective pacing ensures that the readers are constantly on their toes, eagerly anticipating each twist and revelation.

In conclusion, Alanea Alder’s My Eternal Light is a compelling blend of spiritual narrative and celestial fantasy. While it occasionally stumbles under the weight of its own complexity and the conventional leanings of its romantic subplot, the novel remains a formidable entry into the fantasy genre, marked by its rich world-building, dynamic characters, and profound thematic inquiries. Readers who are drawn to stories that combine elements of fantasy, philosophy, and romance will find Seraphina’s journey an enlightening exploration into both the external and internal realms of light and darkness.