Counterattack System appeared when I'm already At The Mahayana Realm - Chapter 21 - Two Dead Cities

The daughter of a duke, the stuttering Maximilian, married a knight of lowly status at her father’s coercion.

Masterpieces such as 'The Divine Comedy', 'The Theory of Evolution', 'Encyclopaedia Britannica', 'The Theory of Relativity'...Born in the history of human civilization, possess mysterious and magical powers in another world!Original sin, biological evolution, mastery of all arts...By reading the secret tomes, one can gain a variety of powers!The only trouble for the people of the other world is that they find it difficult to understand the texts from Earth.At this time, there comes a librarian from Earth...

Xiao Yu, who was a student from modern Earth, accidentally transports to another world and becomes the lord of a territory. Facing an unfavorable situation, he vows to take back his family business, build his new territory, kill all of those who covet his wealth, and dominate the world!

- Description from Novelupdates

Mauve Grey is finally getting the treatment she has always wished for, her father even openly calls her his daughter. Could life get any better?However, she knows it is for all the wrong reasons. She is finally useful, no longer just seen as the sin of the king, a lustful night with her as a constant reminder, especially to the queen who can't stand her.As if getting married off isn't bad enough, she is getting married to the evil vampire king. The species that have put them in jeopardy many times over.However, she has no say in the matter as this forced union is a sign that humans and vampires were truly at peace. However, Jael is ruthless and proved to be more than she ever imagined.Will she survive the vampire world considering vampires think humans to be no better than animals? Will she hold out being the Vampire King's new play toy?