The Record of Immortals and Demons in the End of the World

I didn't even think about an introduction when I first started writing it, but I'll think about it later and improve it. The main thing is to use the system to cultivate immortality in the apocalypse. Of course, this system is owned by everyone, not just the protagonist, and it's not the kind of invincible cool novel. There are no routines, just write whatever comes to mind, and the plot develops as you like. It may be possible for the heroine, who knows? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.