It is the author's first fantasy novel in almost ten years, following the publication of her science fiction series The Murderbot Diaries.

The story alternates between the past and the present; this plot summary is written in chronological order.

This city-state wants to replace Benais-arik as the leaders of the Rising World Coalition during the upcoming treaty renewal ceremony.

They travel to the ruins of the Hierarchs’ Summer Halls to look for a finding stone, which will help them locate Tahren.

Kai has simultaneously organized to weaken the international support of Benais-arik, causing the renewal to fail and the Rising World coalition to devolve into a set of allied states rather than an empire.

Writing for The New York Times, author Amal El-Mohtar ranked Witch King as one of the top ten science fiction and fantasy novels of 2023.

El-Mohtar wrote that the novel "is an immersive throwback to a beloved species of 1990s fantasy doorstop, full of cataclysmic intrigues between mostly immortal families".

Brown notes that some readers may be disappointed that "Wells doesn’t tell the reader much about the history of the world or the specific events that bridge the gap between Kai’s time in the grasslands, the Hierarchs’ brutal rise and subsequent fall, and the rebuilding of the world left in their wake."

Martini praised the "imaginative bits of scenery" and the relationships between the characters, but ultimately felt that the plot was too confusing.

The review criticized the dual-timeline structure, noting that "The Hierarchs are established as the Big Bad, but we enter the novel in the present day with the understanding that Kai has already defeated them—negating any tension involving the Hierarchs that Wells crafts in the past timeline".