He is neither human nor monster, nor immortal nor ghost. He does not know where he came from and where he is going.
He extradited souls one by one and resolved obsessions one after another; he saw all kinds of things in the world. This beautiful world was just black and white in his eyes. It wasn't until he met her that his world took on a bright color.
However, "good things in the world don't always exist, and the colorful clouds are easy to scatter and the glass is fragile." He searched thousands of mountains and rivers, but could never find her.