After Meeting Miss Death, I Began Saving the World

I'm a genius girl agent, and I lost everything on my eighteenth birthday.

Against vampires with absurd strength, bullets and blades were completely useless.

At death's door, I met Miss Grim Reaper, and she even called me her big sister.

That was when I touched the hidden side of the world.

Should I save the world with her, or have my memories erased and bury my blood feud forever?

The answer is obvious.

I'll save this miserable world with her.