Yang Li has been so confused for decades that he has forgotten everything. Family, friendship, everything has nothing to do with him. It doesn't matter who dies or leaves. He has become so bad that he has no hope that anyone will love him, not even himself.
Yang Li: I am a monster who doesn't understand love
Yin Li: I am a lonely soul that will never die
Intention: From whom does the love that can be guaranteed with "certain" come from? It's yourself