Hastur Lord is a science fantasy novel by American writers Deborah J. Ross and Marion Zimmer Bradley in the Darkover series.

[1] The book falls in the part of the Darkover timeline that the author called "Against the Terrans: The Second Age (after the Comyn)".

Hastur Lord is an allegory, illustrating the consequences to a religiously pluralistic planet, when a small group of monotheistic fundamentalists tries to impose their will on a larger society that doesn't share their views.

In terms of Darkover's timeline, the book takes place after The World Wreckers and before the Exile's Song—about ten years[2].

Dan's wife, Tiphani, is hysterical, regarding Threshold Sickness as a symptom of moral degeneracy, rather than simply an illness experienced by telepaths.

On the journey to Thendara, Rinaldo displays a tendency to lecture and scold, that both Regis and Danilo find disturbing.

Despite threats of open warfare by Valdir Ridenow, Rinaldo thinks it's more important to impose the cristoforo religion on all of Darkover.

He discovers the missing children in an upstairs dormitory, and while attempting rescue, encounters a spaceforce detachment sent by Lawton to recover his son, Felix.

Regis restores paxman status to Danilo, and summons his brother to answer charges in the Crystal Chamber.