Nenrei Seigen-tsuki Otome Game no Akuyaku Reijou desu ga, Katabutsu Kishi-sama ga Yuushuu Sugite R Event ga Issai Okinai

One day, Lobelia, the daughter of a marquis, realizes that she is the villainess of an 18-rated otome game and that, Lily, her beloved younger sister, is the main character.

"I can't let my precious sister be subjected to such a disgusting situation," she said. "And there's no way I was going to bully her!" So begins Lobelia's struggle to change her destiny!

Before her reincarnation, she had favored the prince's knight escort instead of the prince who was the love interest. As it was a rare opportunity, she was hoping to get the knight escort to fall in love with her while helping her sister. However, he is not interested in Lobelia at all. Moreover, the knight escort is crushing every R-event entirely...?

Will Lobelia be able to reach a happy ending?

(Source: Takeshobo, translated)