The Protagonist Must Die

He had been killed by accident, and in order to survive, he had bound himself to a system.
He had only one task, and that was to kill the Son of Fate.
He ended up with a really tough guy, and he got himself into trouble, and when it was over, he regretted it.
About two or three things that Her Majesty the Queen and the Cynical Boss had to say
On the Importance of Learning to Fall in Love