Yin-Yang Coffin, Suppressing Hundreds of Ghosts

My grandfather's name is Yin Shiba, and my name is Yin Shiliu. The surname Yin is not because of our surname, but because of our profession. Grandpa is an old coffin maker. Because she was born with too much yin energy, she has been raised in a coffin since she was a child. On the Hungry Ghost Festival, we closed the store early, but suddenly we had customers come to our door. Grandpa felt like he was facing a formidable enemy, "Today is the Ghost Festival, so we won't make coffins for people." The man laughed sinisterly, "Who said I'm a human!"