The Regression of Great Sage Riddle Episode 4

A young man named Riddle loses all his friends and the entire world to a secret and dangerous organization called the "Box of Malice." After losing everything, he becomes completely devastated and spends his life in a dark hole until he gets one last mind-blowing idea. He wonders—what if he could go back to the time before everything was destroyed? After a thousand years of toiling, Riddle, reduced to a truly bizarre and miserable condition, finally succeeds in time travel (reverse time). He vows that this time he will take them all in stride. Now, with a young body and thousands of years of secret knowledge and dangerous experience, the "Great Sage Riddle" sets out to avenge himself and change the past.