The Incandescent by Emily Tesh

A Deadly Education meets Plain Bad Heroines in this sapphic dark academia fantasy from bestselling author Emily Tesh, winner of the Hugo and World Fantasy Awards

Doctor Walden is the Director of Magic at Chetwood School and one of the most powerful magicians in England. Her days consist of meetings, teaching A-Level Invocation to four talented and chaotic sixth formers, more meetings, and securing the school's boundaries from demonic incursions.

Walden is good at her job—no, Walden is great at her job. But when a new threat arises in the form of the ancient demon who has long waited patiently just beyond the school’s wards, even Walden and the aggressively competent Chief Marshal, Laura Kenning, may not be able to contain it.

It’s Walden’s responsibility to keep her school with its six hundred students and centuries-old legacy safe. And it’s possible the entity Walden most needs to keep her school safe from—is herself.