What is the most disappointing/disturbing thing is that the trash of a protagonist didn't even thought of trying to ask Marina if she needed help, like her getting out of slavery. (She might not be totally suffering, but it's clear she's not enjoying either being a slave and being under someones rule.) They are fellow countrymen/of same (very small) group in that other world, and it would be only logical for them to try to help each others, and even group up.
Same thing with the holy knight. It's weird how these characters don't even talk about their experiences, or try to be friendly with each others. Even the asshole of a holy knight was almost trying to murder the mc even though it was clear they were both japs. I guess less than 0.01% of the population are these wanderers, and probably not all of them are not even japanese (just a guess though).
It just makes no f-king sense for these japanese to act this way towards each others when they finally end up meeting.