Honestly I thought that was established in the first few chapters? I'd have to double check. It's like where he mentioned being born as a prince, he meant it as "Oh, I got reborn as a prince so I thought I could live this life in luxury, until I realized being a prince meant people constantly wishing for my death." His life on earth was never shown explicitly, but it was assumed based on him knowing hercules and such that he came from Earth originally.
Found a quote from the first chapter: "I felt happy when I was reborn into this body... I am a prince! Even though I may be bedridden, compared to my previous life I can now live in luxury."
So we never saw what his previous life was like, but it was stated. And judging by clues like the hercules thing and phrases from Earth like "rabbit hole" and about games, we can kinda assume. Don't think it's terribly important to this story, though, so ye.
Ah ok, ty for letting me know. I guess It completely went over my head early on because it didnt show us anything.
Wait so i just binge read it and I realised that his Story went from "being Born as a Prince" to "oh yeah i got reincarnated to this World from earth" like what why did the author randomly add this after like 25 chapters (started when demon King girl Was added)...