The Book-Traveling System Asked Me to Prevent the Demon Lord from Destroying the World

[Overhead Cultivation of Immortals + Traveling Through Books + System + Growth-type Female Protagonist] Xu Anyao accidentally entered Xiu Xianwen and was bound to the system Xiaoqi. The system only gave her two tasks: to prevent the demon king from destroying the world, and to rewrite the BE ending of the original male and female protagonist. There is no force, no urging, no punishment. Once the task is completed, you can return to reality and realize a wish; but once you fail, you will really die. She was accompanied by System Xiaoqi, two senior brothers, a senior sister, and close friends. She overcame obstacles and grew up step by step. It wasn't until one day that she was shocked to realize that the senior brother who was extremely gentle to her was actually the demon king who was destined to destroy the world. [Lightning protection tips] 1. The whole process focuses on the growth of the heroine + improvement of cultivation + return home. 2. No cp 3. System + artifact two golden fingers 4. Demon Lord is a pure tool man