In Stoutimore’s fantasy debut, swords and magic clash in an ongoing conflict entangling angels, demons, and humans.

In a futuristic world not too distant from our own, the human Knights of Sadira once fought evil armed with the magic of angels. But it’s been six years since their home and training ground burned, and now Knight Raffi Okamoto treks across a dystopian Japan as a ronin, or masterless warrior. She reluctantly agrees to help an old friend, Quincey Henri, a New Orleans–based mage who co-founded a group of powerful “Craft” (magic) practitioners; he needs all of his magical comrades to aid in combatting sinister witches who have unleashed a daunting soul-eater demon. He enlists Raffi, armed with her katana and her staggering agility, to track down his fellow co-founder, Insaf, a former Knight who’s now missing. A concurrent plot, which takes place decades earlier, focuses on an orphaned girl who’s lost her family and most of her memories. After saving her from vicious masked men pursuing the girl in Neo Tokyo, Asahi, a Yakuza boss, all but adopts her, naming her Aiko and taking her into his clan where she trains to become an assassin. Aiko endures the harsh and often cruel training, driven by her obsession to mete out vengeance against the Yakuza who, she believes, slaughtered her parents. The time discrepancy between these dual plotlines gradually diminishes until they converge in a violent collision between good and evil.

Stoutimore’s novel, the first in a new series, unfolds in an indelible cyberpunk world in which many people’s bodies are augmented in some capacity by “mech.” The story rarely views such technological advancements favorably, as air-car traffic clutters the skies and flashing holographic billboards are a nuisance. The presence of angels and demons functions mainly as a backdrop for Raffi’s and Aiko’s fascinating stories. Raffi comes with a mysterious background; readers know little about where she’s from, and a demonic voice in her head incessantly taunts her. Aiko seems like Raffi’s antithesis, but her past is equally murky. Their connection to one another isn’t terribly difficult to work out, as the author starts dropping huge clues well before the halfway point. Stoutimore includes copious action scenes that hit hard and fast, reminiscent of the lethal face-offs in samurai films, complete with severed limbs, spurting blood, and viscera smacking the ground (“Raffi whipped her weapon in a tight spin and closed her eyes. ‘It’s been a while since I’ve gone unrestrained. I thank you in advance for the chance’ ”). This opening installment, despite its length, leaves much to explore: The other five Knights of Sadira make relatively few appearances, and the novel provides few details surrounding the “eternal wars” between the angels and demons. The smashing conclusion of this opening salvo is sure to have readers on the lookout for a sequel.

This epic tale introduces a cast as unforgettable as the future world they live in.