Vampir Lord: Erotic RPG - 67 Chapter 18

Xue Xi is forced to fall in love at first sight with this dangerous man on their first meeting. With death being the only other option, she makes the first move:

On one spring evening when I was eight years old, I, Erica, Duke of Aurelia’s daughter, realized something.

A terrible calamity has fallen onto Zhang Fan, not only becoming one of the three survivors of Grass Temple Village, where everyone else was horribly massacred, he was also tasked to carry one of the most evil artifacts, the Sinister Bead, and taught one of the most secret teachings of the Skysong Sect, the Brahmin Wisdom. Now he cultivates in the Jadeon Sect, his knowledge and possession will draw him into a chaotic story where he will have to carry some of the greatest burdens of the Martial World.

There was a Senior Brother and a Junior Sister. One of them was transmigrated to this world and had cheats while the other was the reincarnation of a Great Emperor.