HxH : Pokemon Master - Chapter 18: The Samok Desert

When she opened her eyes again, she transmigrated and become a foolish woman in ancient times, Chen Afu.Gazing at the hero who seemed as lofty as a god, Chen Afu touched the drool trickling from her mouth. In this life, don't be too ambitious, don't be unrealistic...Only, in this life, she was foolish yet beautiful, destitute yet incredibly lucky, her good fortune so plentiful that she couldn't use it all up.

She, a modern hidden ghost leader of an organization which gathered insane prodigies proficient in the various differing skill-sets. Highly skilled in medicine and poison, executes covert assassinations, viewed as insane and demonic in the eyes of people of the world. Killed in an accident, and reborn into the body of a disfigured young girl.

What? Face disfigured, identity stolen? A return to the family dim and hopeless? Her identity can be given up, her family can be forgone, but as for the one who harmed her predecessor who inhabited this same body, if she didn’t at least make them scream in unimaginable agony and throw them into a state of wretchedness, how could she live up to her demonic reputation? Endless turmoil ensues and it’s a battle to dominate over all! See how she shook the world dressed in a suit of red, her sword up against the dominant powers that rocked the Heavens! Her name spread across the seas, shocking the earth!

- Description from Novelupdates

On the surface, he is the aloof and standoffish patriot whose sole purpose is to serve the nation. On the darker side, he is an invincible, powerful and mysterious man.