The novel was a quick transmigration that I read few years back, when I first got in touch with QT troupe. I only remember that it was a cultivation arc, where something happened to the FL or her system, so that she had to die(?) or leave. The ML was searching and waiting for her for years, as in many many years. And when the FL came online (?) again, she was in a spirit form, cause the system needed to build a body or something. She found that the Male Lead was already old with wrinkles waiting for her and followed him in spirit form. After she came back to life, met the ML but the ML felt something (?idk) and told her that he was already old. Then some things that I don't remember happened and the male lead was in his prime age again. Done! Basically, this is what I remember but forgot which novel was that. Please help me find this novel. It's really getting on my nerves that the novel is almost at the tip of my tongue but I don't remember. You know this feeling right? Please help me!!!