I grew up across the street from a police officer. One day he came home with a used chihuahua. The chihuahua and its prior owner had been in a car accident. The chihuahua was in full demon mode and successfully defended its owner against the first responders - it would not let them get near. The man died from his injuries (because the first responders could not treat him), and the demon chihuahua immediately adopted a new familiar - my neighbor who had arrived on scene. “Old human slave dead, you are my human slave now” sort of thing. The dog loved my neighbor and followed him everywhere. It loathed this guy’s wife and daughters (and everyone else) and would snarl at them and try to bite them if they came near “his” human.