I became a villain master, but I conquered the heroine

The beautiful master who only wants to live a salted fish life vs. the arrogant, black-bellied and paranoid apprentice Yuanchu was bound by the system and was asked to rewrite the ending of the heroine Gu Xi's world collapse and save the world. The system told her that after she played the role of the heroine's master well and completed the main task according to the system task prompts, she would be sent back to her original world plus 100 million as a reward. That's a full 100 million, who wouldn't be tempted! Yuanchu bowed to the God of Wealth, only thinking about how to complete the main plot and live a perfect salted fish life to the end. But... who can tell her why the plot direction has changed? And it has become so outrageous?? With the voice of "Master" full of attachment...