SOLVED: Hero is a cult member who abducts heroine. Very dark romance.

I haven't read this book. All I remember is from blurb and reviews.

It's really dark, heavy read. I'm not even sure if it's a romance at all.

Girl is kidnapped by the hero. He is a member of a cult and totally brainwashed.

He tortures her and rapes her repeatedly because the leader of the cult tells him to (?).

If I remember correctly hero was abused for years, since he was a boy. Physically and mentally broken to pieces and reshaped into a fanatic and loyal cult fallower.

Heroine makes hero question the world he's living in.

Book is an installment 1 of the series and hero and heroine escape the cult at some point.

I think there is a word PUPPET on the cover.

For some reason, I was sure it was an author's pen name but I couldn't find such an author so now I'm leaning toward "puppet" being a part of a title.

ETA

I found it.
It's Darkroom Saga by Poppet.