Lord of Shadows by Cassandra Clare

The second book in the Dark Artifices trilogy follows Emma Carstairs,
Julian Blackthorn, and their parabatai circle in Los Angeles as they
investigate Malcolm Fade, navigate Faerie courts, and conceal Emma
and Julian's forbidden love while Mark Blackthorn's relationships with
Kieran and Cristina complicate the Cold Peace.

This book contains; alcohol, alternate gender or sexual ideologies,
body horror, dark content (witchcraft/magic), death and grief,
deception, demonic content, derogatory terms, discrimination, dubious consent, gender dysphoria/transgender content, gore, hate speech, horror, mental illness, murder, non-sexual nudity, oppression, parental neglect, patently offensive sexual content, profanity, sexual activities, sexual dialogue, stealing, suicide, toxic relationships, and violence.