MTL - Rival In Love Says He Must Marry Me - Chapter 9 hair dye is poisonous

Arnold never thought his gaming skills would land him in a romance novel—as a doomed side character, no less. To survive, he hijacks the heroine's “system,” bending the story to his will. But when he dodges a deadly duel, he catches the eye of the heroine, Lara, his own step sister—and her love is a dangerous game. Arnold must outwit the plot and his step sister who's not afraid to kill for love. In this LitRPG romance gone wrong, survival isn't just about beating the system—it's about escaping the heart of a yandere.

In order to chase down and kill her own murderer, Xia Yichu reached an agreement with the 233 system, and she will travel through the world to complete the task, and The 233 system helped her return to the original world.
However, Xia Yichu often encountered a broken BOSS while he was on his way to do the task. He did n’t agree with each other on the wall, the bed, the various patterns, and kept talking.
System: Please use one word to describe the other person’s impression in your heart.
Xia Yichu: Competent.
Shen Jiaye: Mine.

- Description from 69shu

The heavens and earth are furnaces, every living things are charcoal, and the Yin and Yang are fuel. The battle for destiny, fate, and luck between the Serpent and Sacred Saint Dragon arises. When all is said and done, will the Serpent emerge victorious or will the Sacred Saint Dragon rise up above all sentient beings?

Madeline Celeste d'Aumont is the first daughter of Duke Aumont and Duchess Louise-Marie d'Aumont who has been engaged to the Second Prince of Pays Des Abrutis since she was a child. The Second Prince decided to marry a woman closer to his own age and broke off the engagement to Madeline who was left with a broken heart and a reputation as being an unwanted woman even before she was an adult. The Duke decided to help his daughter regain her confidence and reputation by sending her to the Academy de L'échec.

Ito Aoi was the son of a Kendo master who ran a dojo in downtown Tokyo. One day while crossing the street to get some Yakitori, Aoi was hit by a delivery truck and woke up as the trash first son of Duke Montfort, Guy de Montfort. Duke Montfort also sent his son to Academy de L'échec only Aoi instantly recognized that he was now living in the world of an Otome Game that his sister loved to play and talk about all the time. Aoi recognizes that Madeline is the villain from the game. Aoi also recalled his sister saying that Madeline was terrible in the game, but is she really?