Yan Jin is the lone soul in charge of the Yin coffin. He has fed the coffin with blood for thousands of years and suppressed the cracks in the underworld; Shen Xiao is his nominal "sister", but he never touches the coffin and only whispers the forbidden curse on the first night of every month. Everyone thought she was the pallbearer, but little did they know that she was a sacrifice nailed alive into the coffin and filled with blood—the chain of soul wrapped around her, and the warmth of her heart continued to nourish Yan Jin's Yin Qi. When the coffin lid cracked and there was the first trace of blood, Shen Xiao finally asked with a smile: "You really don't know that I am the coffin, and you are the ghost who survived by sucking my life fire?"
