Bo Dennis is the main protagonist of Lost Girl. She is a succubus who was raised by humans when she was little. She ran away when she accidentally killed her first lover, Kyle Williams, while having sex. She ran from one place to another after having accidentally killed many people.
After saving a girl named Kenzi from a rapist, she was taken by Detectives Dyson and Hale. Dr. Lauren Lewis told Bo that she is a fae, which are a type of supernatural beings. Bo is specifically a succubus. Bo is put on a test of physical and mental strength. After passing (with Kenzi's help), she is told to choose between the Light or Dark fae. Bo instead chooses humans.
Bo and Kenzi later set up a private investigator service which involves cases related to fae. All the while, she tries to learn of her past and is in a love triangle with Dyson and Lauren.