Got me thinking. Now that we have established the entire plot of Eternum takes place within the same universe as OIALT, i remembered there was a magic tome/book left behind by OIALT MC during the ending. And with how Stabby Mike had become a prominent figure (a college graduate, the president) in the Eternum timeline, it is safe to assume that Eternum takes place after OIALT. We don't know for sure how long, since we remember how Stabby Mike can attain fame and power in an instant (like how he became a well-known church pastor in less than a week). We also saw Thanatos has somewhat inhuman powers, like maintaining consciousness even after violently bleeding out from a severed hand.
Correct me if i'm wrong, but from the little i saw; although other Eternum players (except Orion) can have special abilities at higher level, it (the others' special abilities) did not seem to make them able to overcome their humanly physical limitations (physical durability, physical strength, any other physical attributes). We saw how this might not be the case with Thanatos. There was even a myth of Thanatos' invincibility within the Eternum playerbase. And it is unlikely for a game of hyper-reality MMORPG such as Eternum to grant cross-server invincibility to a player after reaching a certain level.
So perhaps Thanatos' powers is not obtained from the game itself, meaning he's probably inhumanly powerful even outside Eternum (in the real world).
If you haven't caught on to what i'm implying, perhaps Thanatos is someone in posession of said tome. Keep in mind i don't remember exactly what powers that tome offers. And the reason why he would choose to operate in Eternum (first, and not wreak havoc in the real world) was because of the rewards of gems of doom hunt. Regardless of his motives or plans, gaining power of such magnitude (CEO/owner of multi-billion dollar company) will at the very least assist his presumably villainous schemes.
Yet still don't get how Thanatos appears to understand, or at least know, the purpose of Calypso's creation. I believe this is implied by his line "You don't even know why you were created" in his dialogue with Calypso nearing their escape from Ogygia.
Based on this fact alone, i assumed he is some Ulysses exec looking to seize power from the founder. And coupled with the classic trope of "the big bad guy was already teased from early on in the story", it made me guess it is William Bardot. But when we combine this conclusion with my arguments in other paragraphs above, there seems to be a huge missing link. Hopefully this makes sense.
I understand that my theory might be farfetched and biased. At the very least, i hypothesize that the tome in OIALT will play a role in Eternum's plot.
