Summary:

Areum has fallen into a strange world called 'Soltera' after a car accident.
She is mistaken for a vampire because of her hair color, and she is sold to a Duke’s house by a slave trader.
The identity of Millard Travis the master of the Duke’s house that bought her is the one and only vampire in the world!

Desperate to survive in any way, Areum becomes Millard's direct servant, vowing to serve him as her master.
Areum tries to belly up on Millard day by day and his attitude starts to change.

Resources:

https://www.netcomics.com/comic/themaidandthevampire
https://www.ecomix.com/comic/%ED%95%98%EB%85%80%EC%99%80-%ED%9D%A1%ED%98%88%EA%B7%80-%EC%97%B0%EC%9E%AC
https://www.lezhin.com/ko/comic/maid_and_vampire