The Sword Breaks the Heart

A young man accidentally traveled to the earth 2.6 Billion years ago in search of his sister. At this time, the earth is experiencing a different era. This is an era without magic and technology - the True Martial Era. Here, there are only practitioners, where humans, demons, gods and demons coexist. Let's see how the young man reaches the top and breaks his heart with a sword. (Note: I wrote it on a whim, without an outline or background. It's considered improvisation. I write whatever comes to my mind, so it's understandable that the update is slow)