Unholy Union Books in Order

The Unholy Union duet is an arranged marriage story that feels more like a countdown to impact. Split between Unholy Union and Unholy Intent, it follows Cristina and Damian Di Santo, bound together by one terrible night and eight years of waiting.

Cristina meets Damian in a dark corridor of her family home when she is still a scared girl and he is already a man. From that moment, dead roses and sharp thorns mark each passing year as she moves closer to the eighteenth birthday when he will come back to claim her. She grows up knowing there is a monster with her name on his lips.

When Unholy Union opens, that countdown is over. Damian returns on the eve of her birthday to collect on the promise etched into both their lives. For him, the marriage is about power, protection, and settling old scores. For Cristina, it is a trap she has seen closing in slow motion, one she still fights against even as she walks down the aisle.

Their dynamic is charged from the start. Damian is unapologetically possessive, convinced that only by keeping Cristina in his house and under his rules can he keep her safe from enemies they share. Cristina sees only the man who ruined her sense of safety and the life she thought she would have. The first book is full of claustrophobic tension, locked doors, and the strange comfort she slowly finds in the arms of the very man she fears.

Unholy Intent pushes deeper into the Di Santo family’s secrets. Damian has wrested control from his brother and put himself at the top of a criminal empire that has more enemies than allies. Cristina learns that the lock on her bedroom is as much to keep monsters out as it is to keep her in, and that her husband’s ruthlessness is often the only thing standing between her and people who would happily destroy her.

What makes this duet compelling is the way Knight lets both characters be wrong and right at different moments. Damian’s choices are frequently unforgivable on the surface, yet his devotion is real. Cristina’s resistance is understandable, yet her heart keeps reaching for the man she knows she should hate.

Unholy Union stands on its own but will feel familiar if you have read other arranged marriage series by Natasha Knight. It offers the same mix of high heat, high stakes, and an ending that acknowledges the scars they both carry.