Mated To My Obsessive Stepbrother

Trigger warning!!!
Intended for mature readers who enjoy morally complex, slow-burn, possessive, forbidden, dark romance that pushes boundaries.
EXCERPT
Blood everywhere. Trembling hands.
"No!" My eyes blurred.
His lifeless eyes stared back at me, his blood pooling at my feet. The man I loved—dead.
Killed by the one person I could never escape - my stepbrother.
Kasmine's life was never hers to begin with. Kester, her stepbrother, controlled and monitored her every move.
At first, it was all sweet and brotherly until it began to turn into an obsession.
Kester was the Alpha, and his word was law. No close friends. No boyfriends. No freedom.
The only consolation Kasmine had was her twenty-first birthday, which was supposed to change everything. She dreamt of finding her mate, escaping the sickening control of Kester, and finally claiming her own life. But fate had other plans for her.
On the night of her birthday, not only was she disappointed that she wasn't mated to the love of her life, but she found out that her mate was none other than him - Her tormentor. Her stepbrother.
She'd rather die than be mated to a man whom she had known as her big brother all her life. A man who would do just anything to make sure she was his.
But when love turns to obsession, and obsession turns to blood, how far can one girl run before she realizes there is nowhere else to run to?