MTL - Fantasy System - Chapter 504 Upgrade task?

Katherine Zara, a single middle aged office worker, went about her day as she always had; wake up, go to work, come home and read or play games. However, today would be different. Before she left for work, her ex broke into her apartment and killed her.

When she woke up, she was given many choices. She could pick her new world, pick her starting point, and pick her system among many other things. And so Katherine decided to become a servant to a villainess.

Follow Katherine as she serves her petty, demanding mistress in a world of swords and magic.

Additional: The Female Lead (Katherine) will be submissive to her mistress, but will be cold towards others. I plan on having some action, but mainly this will be a story about Katherine serving her mistress and leveling up her system.

The story is about a boy entering high school, who answers a strange call from a public phone one night. The caller challenges him to a bet: She’ll remove the birthmark which he sees as the cause of so many problems, and he’ll have fifty days to win the heart of a girl he’d considered far beyond his reach. And with this, a very strange summer begins.

He was not a human since no human is aware of himself even before his birth.

He has no blood and no heart, but emotions?

He does have feelings, but can he express them?

Why was he called a Devil’s Spawn at his birth?

Why did they cut away his arms and a leg?

Why did no one ever visit him for years?

And why does this emptiness... feels so... just so familiar?

Why does the Void feel so... full?

Who is he? Or rather... What is he?