Xixiegui Xiaojie De Qifu Youxi

The ancient vampire Elena transformed herself into a gothic loli to keep an eye on her blood prey, the cursed bounty hunter Chelsea. Elena pretended to be Chelsea's fiancee, but ended up forming a binding contract with her instead. Elena thought she would have to force her to obey, "Bow down before me and become my blood slave, Chelsea…" But her attitude turned out to be more like, "My little angel, I beg you, please bully your Chelsea." Now Elena is all confused. What to do with her masochistic fake fiancee?

(Source: Bilibili, translated)