I don't think OiaLT mc made the game due to the fact that it was referenced to be in development during the events of the game, I also don't thing the MC of eternum made it either due to the fact that he has childhood friend who would most likely know of it or there would atleast be some proof. Personally with the way the creator looks, I suspect the creator might be a decendent of Magnus he has eternal life so maybe before he became the walking corpse we all know and love he bore a child with a concubine (you know how rich people are, especially for his time) I think the kid grew up and went on his own little adventure to find out more about his father, although I'm also half suspecting the developer to be a follower of our beloved protagonist or atleast one of the 5 princes. You know how obsessed he was with eternal life so what if he was also interested in alternate worlds and thus ordered the development of eternum. Astoroth probably has quite a few connections see as how he supposedly has lived for a long time. It kinda reminds a bit of comic called eternal club. To keep it short the MC is bestowed the power to control time. He can manipulate it aswell as store and give years of life time to himself or others. In the comic his organisation eternal club is working on creating miniature worlds with ecosystems and life of its own by using his control of time to speed up the process of development on said "small world". It makes me think about what astoroth may have done to learn of eternal life and what kind of experiments he did to create or simulate eternal life. So yea personally I think the creation of eternum is connected to astoroth. Plus with MC in OiaLT leaving the book in a random edge it makes on think of the power in the universe. Makes me excited for 0.5 after that ending in eternum. I hope I'm right about this to be honest.
the MC of OIAL could have joined the company after it was made and used the book to make himself the new boss and/or the top CEO. And if all of the Orion's friends are NPCs in Eternum or just brainwashed players, they would only know what the company allows them to know. Not that I'm saying I'm right and you're wrong. I'm just saying we're getting unreliable narrator stories here.
In the end I just hope the new MCs don't let people suffer in Eternum for too long before they put an end to it. Right now they played for months. But if it turns out it's been years and years of people raped, killed, bribed, and lives scarred and ruined. I won't be happy about how that ends. Even if Orion becomes king of Eternum. If he doesn't do better than the corruption CEOs and cults and shameless psycho trolls like Thanatos then he is just oartnof the problem and not an MC I wanna play as.
Nope since you know something from Oial i don't want to spoil
But the women who could see future clearly told that mc will never be rich no matter what,and that came true in the end,not going to end up as hobo but just middle class not some rich billionaire and since that simple line was followed till the end i don't think that dev will change it,for other story plot.