Theories about that?
Also noticed that everybody is wearing half gloves, so you don't see whether they have a mark or not, which makes me wonder if some of the characters might be isekai'ed too. This is especially weird when you remember the rumor that states that the enemies were attacking to take things "back to their world" and that they're out for feMC in particular. The obvious thing to assume would be that MC is actually a native (the mark) and feMC the isekai'ed character, but that raises even more questions.