I am your scabbard, and you are my sword.
I am your knight, and you are my king.
A sword without its scabbard will be damaged and lose its edge, while a scabbard without a sword has no value or purpose.
A king without a knight to protect him will sit alone upon his lofty throne. A knight with no king to protect will spend his life in emptiness.
A scabbard exists to protect a sword, and a knight exists to protect a king. You are both my king and my sword. The purpose of my existence is to protect you upon your lofty throne.
My king shall forever be named Artoria Pendragon.
No matter what world I go to or how much time passes, the blade within the scabbard will never be damaged, and the heart of the knight will never fade.