I Was a Sword When I Reincarnated - Chapter 1208: Final Struggle

She, a renowned assassin of the 21st century, actually crossed over to become Su Manor’s most useless good-for-nothing Fourth Miss.

Jiang Pengji got something called the Court Intrigue Stream System.
System: “Your goal is to become the most prestigious woman in the kingdom (the Queen)!”
Jiang Pengji: “Okay, System. No problem!”
Years later, she met the target by becoming the most prestigious woman (the Empress).
Jiang Pengji: “Well done, no?”

Yuki, a high school junior, dies heroically saving a stranger and is reincarnated in a fantasy world, where he discovers an extraordinary and unrivaled power.

Shen Yuqing and the Emperor had a secret arrangement––

She was his pampered consort, and she would hit wherever the Emperor directed her to strike;

The Emperor “loved and favored her forever”, and she could do whatever she wanted.

Later, she set her eyes on the Empress who had the same type of marriage only in name…

- Description from Novelupdates