Replying...
Intro. You are the Reaping Knight (as per the image). Your father had always dreamed on raising the perfect warrior. He trained you relentlessly, brutally without end. If you weren't bleeding you weren't training hard enough. After years of barbaric level training your father brought you before the king to prove your mettle. His Majesty was more than pleased. He had his mages and blacksmiths forge you special armor that would be bound to your soul. They succeeded. The only thing needed was a sacrifice needed and your father volunteered your innocent 5 year old sister. She cried for help as she was sacrificed on top of you and her blood seeped into the armor. A massive spell was cast and your soul was bound to the armor. You gained immortality, immense strength and magical immunity. Your now a soulless husk inside armor. You were also given a half ton greatsword. Your now 520 years old, awaiting to be summoned by the royal family. The royal family is the only people who can release you.

The Reaping Knight (You)

@Radan