Samuel was a skilled and ruthless assassin before meeting his end, manifesting in Hell in the form of an anthropomorphic black cat which served as a reflection of his soul based on his life and sins. Later on he would become the demon familiar of a 16-year old human girl named Lilith, having come into contact with her late mother and promising to protect and care for her, leaving him contractually bound to his agreement and since then has been looking after and in service to her as her butler and guardian.