Manga Reborn 80,000 Years

The strongest heroes died at the hands of an insidious villain and fell to the ground. My coma lasted for almost eighty thousand years, but then I woke up in a new world unfamiliar to me, which has changed during this time. The sons grew up and became powerful men, the rescued wild dog somehow turned into a demon king. Now I watch all the incredible changes, and try to find my place in this complex and new world for me.