They Bite - The Nyxia White Stories, #1

Sleep tight.don't let the bedbugs bite.when the monsters come hunting, call Nyxia White. Nyxia White isn't entirely human. She sees the things no one else can. She never counted on being called to The Seven, it was an offer she could've refused.if she wanted to die. Now she's one of the beings tasked with protecting humanity. When creatures start escaping the darkness and claiming human lives, Nyxia is the one who will stand against them.
Together with her demon familiar, Acheron, and dark magic, she will answer the call and fight for those who can't fight for themselves. When monsters come hunting.she will be their nightmare.