Sister, I Am Chasing the Edge and I Am Passing Through the Fleeting Years.

In a book, the villain Lu Chengyue kills everyone and is in tit-for-tat with the heroine Yun Ying. Everything stems from a fight by the pond when she was a child, and our heroine Lin Siyun is a little cannon fodder who died at the age of three, and the cause of death was precisely because of a fight between the two. To find out why, read this book. PS: I can't make do with my profile.