Thank you for replying and also thank you for your insight. (and sorry if there are any grammatical errors, english isn't my first language)
I have to say that, I think that you are probably right, especially if the story truly follows a greek myth or lovestory.
My happy ending for the two is probably just wishful thinking (I still would be extremly happy if they get their happy end).
But there are a lot of indications that there won't be, like the examples that you brought up in your post.
Especially if we get a longer update next time, where they are on a lovely getaway together in Asterions secret hideaway.
But I have to say with the ichor being toxic to humans: it's also described to be killing them instantly if they came into contact with it.
So either it has lost alot of power over the centuries that it has been in the valley or Hermes basically sent the MC on a suicide mission.
Regarding the powers of the Hotels Master, don't get me wrong, that makes him really powerful but not to an extent that would be useful for this task.
I don't think that he would produce/create a whole lot of guns, tanks and rocket launchers to make the task easier.
I also don't know/remember how it is with poisonous substances.
So the most he could do in this instance is create rations, equipment and maybe swords, but given that we don't know what those creatures might be and what powers they might have, that might be helpful or not. Also our mythical friends don't seem to posses any powers that are out of the ordinary so they might have the advantage of numbers but that's it.
The task is also basically that you get the ichor back so the gods might be restored to full power, isn't it?
And since most of the gods, at least from what I believe Hermes said, came to the realization that the judgement of Asterion was unjust/too cruel. So yes, after gathering the source of what the labyrinth was made of and it might be non existant after that, that also means the MC looses everything that he had.
His powers are gone, Asterion might be sent back to the underworld and since the Hotel doesn't exist anymore the mythicals probably also have to get back, taking their passports with them which makes the MC forget them all.
And even if they take a group-picture or something, won't that (in the worst case scenario) make the MC be rewarded with a place at a psych-ward? With him maybe trying to convice others that there are mythicals out there? And even if he just forgets everybody, the photo might than just look like a photo taken at a very impressive furry-convention.
So granting him the title off a demi-god or a hero of greece, might just be that: granting him a title, but that might also grant him access to the greek afterlife where he and Asterion might be reunited.
And with the hotel not existing anymore there also won't be any issue with the position as a Master being in conflict with the title/Status of a Demi-god/hero since ther is nothing that he is a master of.