Iron Flame by Rebecca Yarros

Follows Violet Sorrengail's return to Basgiath War College after the events of "Fourth Wing".

This book contains; alcohol/drugs/smoking, alternate gender/sexual ideologies, animal cruelty, assassination, death, gender
dysphoria/transgender, gore/torture, manipulation, obscene sexual
activities/sexual nudity that are shown on the page, potentially patently offensive content, perilous situations, poisoning, profanity
(graphic), potentially prurient behaviors, volience (intense) and war/battle/brutal injuries.