Fallen Kingdom Series by Rachel Leigh

Genre: NA; Contemporary Romance

His Hollow Heart is a dark romance with triggering content. This book ends with a mild cliffhanger, but do not worry, Bella and Callum will get their HEA, after they work hard for it.

His Hollow Heart (Fallen Kingdon #1) - Blurb 

Bella
A pact made.
Two orphans who vowed to never part.

I was selfish—for once, I had to be.
The last time I saw Callum he was standing at the dormer window as I sat in the back seat of a car.
His dark eyes foreign to me.
The hatred that radiated from his glare shot through me with more force than a silver bullet.
In a matter of minutes he had become a stranger.
He was no longer my best friend.
He was now a boy with a hollow heart who was headed down a dark path.
A path I knew I’d never cross again.
Or, so I thought.

Callum
We had a deal—always stay together.

The day Bella left, I vowed I would find her. And when I did, she would feel what I felt as I watched her pull away into a new life, with a new family.
Leaving me behind to endure a life that was wrapped inside the hands of a monster.

It’s been twelve years, but I’ve finally found her.
Now it’s time for her to bask in the darkness she’s created inside of me.