How Did the Loyal Dog I Picked up Turn into a Big Boss?

It snowed heavily in the middle of winter, and the cold penetrated to the bones. She picked up the boy. The two clung to each other through the stormy years. She thought she had a docile and obedient loyal dog, but no one knew that the desire and obsession in the young man's heart had already grown crazily in their company day and night. His unwillingness finally turned him into a bloodthirsty evil spirit...