R.M. Lee 
The Immortal Beside Me Part I 

Book I is about a reluctant werewolf, Nikolas Tackett. He married a human, she became pregnant, and she died during childbirth. His son, whom he named Keagan, he notices a small mark on the boy »s hand that has always meant a live birth is actually a werewolf in the making. His meddling sister in-law, Sophia Apton, arrives to help Nikolas. Although he does not need her, she remains. They clash and Nikolas turns her into a werewolf. Mayhem ensues, as Sophia kills for sport. Her prey items: human. Nikolas does not feed on humans and must fight to end her life.