Heh, Robert was only a red herring for me in a sense that he's a big and intellectual demon who is a hottie. (Pun not intended but totally appropriate).
This topic does make me wonder if one of the themes of Minotaur Hotel, whether intentional or not, how much trust one puts into the social contracts. (Really appropriate term now that I think of it.) While we don't expect everyone to tell us their whole lives story upfront and as honestly from their perspective, we do have an expectation of honest that even the smallest and basic amount of information exchanged is the truth. We see this a few times with names such as with P and Jean but we also see it openly challenged a few times by Asterion, albeit playfully most of the time. Why is Asterion under any obligation to outright tell the MC the whole truth and nothing but the truth unless he's forced by his contract? And even then, he is able to find loopholes to withhold information as he pleases. There's also the story about the pyrite crucifix which reveals a lot about how cunning Asterion is with being able to bend truths which I highly enjoyed.
This narrative makes me question this aspect of our social contract in humans though one does also have to be careful not to fall too hard the other direction and start to question every single thing presented. There is a mystery to the narrative but I haven't been giving a reason to suspect that we have an unreliable narrator (though I do question if the narrator outside of the Hinterlands chapters is just a narrator or an in universe omniscient character) so I don't tend to question every single word presented in that sense. I also don't quite question what the characters present of themselves unless I'm given a reason to (the mysterious vibe and some of the things Jean says or doesn't seem to say makes me question his identity for example.) In addition, just because a character doesn't present the whole truth doesn't mean their actively being deceptive, they could just not have the whole truth themselves. (Something I suspect when it comes to Asterion and the topic of his sentence.)
I'm not sure if I got my thoughts across but I feel like if I go one, I'd just be rambling.
TL;DR: Questioning the humanity's social contract one of the themes? I trust Robert to top him or bottom for him without getting burned. 🙃