The man once known as the strongest sage reincarnated as a 6-year-old boy – Eddie. Having retained the memories of his previous life, having exceeded his previous peak, he came to a decision.
— To stay in the shadows instead of becoming the greatest sage.
Eddie buried his memories of obliterating the Demon King and enrolled in the Royal Academy as a normal 6-year old boy.
Of course, after the death of the Demon King, he nurtured his retainers and acted as the Ruler of Darkness in secret.
Sometimes the Ruler of Darkness. Sometimes a freshman in the magic academy.
This is a story of the strongest juvenile sage and those who swore loyalty to him.