In a world where humans and shifters coexist, every shifter is raised with a single purpose: to serve. Born as beings capable of shifting between human and animal forms, they are expected to be obedient, loyal, and devoted to the human who adopts them. Once chosen, a shifter dedicates its life to protecting and caring for its owner, often forming an unbreakable bond. Some shifters even leave a mark upon their human-a symbol of absolute trust and lifelong loyalty that deepens their connection beyond words.