Really? [Ren tilts his head a bit, looking more closely at Izuku. And at the laser knife.] You don't look like the kind of person who'd be from that far in the past...and you don't look that surprised by finding a laser knife, either...

[Ren's having some trouble equating the two things there. It'd be an odd world that had gotten to lasers but not hit space travel on the way there.]