MTL - I, a Demon Slayer Girl, is Invincible! - Chapter 4

Evan crossed over, but he wasn’t worried at all… because he had the character template from the mobile game and five devil fruits obtained from a lottery draw with him.

After Gu Jinghe passed through the book, she became a cold and ruthless overlord. The system asked her to abuse her heart and body against the poor heroine, and the world was broken.
The heroine is both beautiful and miserable, Gu Jinghe couldn’t bear it, and decided to put on another vest to secretly compensate her.
She seamlessly switches between old and new identities, and lives like a genius every day.
When she was the overlord, she looked cold and stern, with a mocking smile on her lips, and her fingers raised the heroine’s chin: “Ji Yunyan, the fate of the Ji family is in my hands, you’d better be obedient.”
In her new identity, she smiled brightly, and her voice was sweet and soft: “Yanyan, can I go to your house to do my homework?”
Probably because of her superb acting skills, the heroine treats her with a cold face as the domineering boss, and smiles like a flower at her new identity.
Until one day, when Gu Jinghe routinely confronted Ji Yunyan as the boss, Tian Liang Ji Po, Ji Yunyan suddenly called out her vest name to her.
Gu Jinghe agreed…
Gu Jinghe: Why don’t you listen to my explanation?
Ji Yunyan: (smiling) Make it up, keep making it up.
[The story of two people who thought they were straight but were not so straight flirted with each other, and ended up breaking themselves completely]
(The cover is the persona of Mr. Jing Heba)
Ba Zong and Jiaojiao seamlessly switch between the superb acting skills of Shou vs. the attack of the disguised little white flower

Content tags: system sweet text wear book
Search keywords: Protagonist: Gu Jinghe ┃ Supporting role: Ji Yunyan ┃ Others: Chuanshu, Overlord, Actress
One sentence introduction: I fell off the horse in front of the heroine
Intention: No matter what difficulties you face, you must stick to your own nature and not fall into darkness. the

- Description from novelbuddy

This is a story of an ordinary boy gaining unusual powers from his nightmares… It all started when Lin Sheng experienced something strange on what he thought was just another normal day. He begins to have recurring dreams that lead him on an incredible journey of discovery as he encounters spine-chilling monsters and elusive secrets.

- Description from Novelupdates

The second prince has come of age. To celebrate the advent of such an occasion, the search for a suitable bride began. My younger sister was expected to go to the Royal Palace as a candidate. However, despite this, she eloped the day before her departure. I, the older sister she left behind, looked almost exactly like her – so much that we were often mistaken for twins…

One month, right? For just one month, shall I substitute in for my sister?