What If I Can't Die?

[Song Shi came to an immortal world where demons and monsters were rampant. He thought he was going to take a trepidatious road to immortality, but ended up awakening to a death-defying system, gaining strength from death and getting stronger every time he died., The whole style took a sudden change. Other people cultivated to seek immortality, but he was already immortal, and could only seek immortality by having himself killed in various ways, either by killing himself or by letting people kill him.\