Greatest Boss System

A brief description of the Greatest Boss System manga:

Who is he and why are they calling him the Boss? Is he the oppressor of the Celestial Empire, who rules every corner of the universe, or the enemy of all men, who stirs up worlds? After his rebirth, the system was built into him and now Su Sin can get back all his skills and fighting abilities from the world of knights from a past life. “My name is Su Sin, Sin means holding the Word.”