Neat, they're basically very high-class mimics. Not unlike the eponymous Thing from John Carpenter's The Thing, just without the shapeshifting. Highly intelligent and capable of mimicking behavior, speech, and social cues but totally different on an instinctual level. Even if you implanted human...
MC is a loser. He's clearly the more experienced and battle hardened warrior, and on top of that he's a former roaming mercenary, older, and by far the superior physical specimen to everyone else, but he acts like the typical Japanese isekai dweeb who can barely speak up and set these preteen...
No one remembers that he literally had the ability to turn invisible and change his voice and body through magic (now psychic) powers earlier in the series? They weren't subtle about it, he even said he couldn't use his powers for over 6 months the last time he metamorphed into Ron and it showed...
It was mentioned that the medicine of the world is about 100 years behind Earth, so a m1911 isn't totally out of the question. These countries may not be the most advanced on their planet. They also had an EKG earlier, which is from the turn of the 20th century
Guess those people in the ferris wheel are just dead
Also, the hero totally betrayed humanity. There's only one human kingdom left and he's just flirting with the demons smh