Gansui is a herbaceous plant in the spurge family. Its root is used in medicine; it is cold in nature, bitter in taste, and poisonous. It perfectly symbolizes the protagonist: he can save lives, yet carries a deadly poison within him, the torment of immortality, condemning him to loneliness.
· In a sentence: Gansui can save others, but cannot save himself. Over three hundred years, he personally bids farewell to everyone he loves, becoming the last heartbroken soul in the mortal world.
