JKSManga
There is another conclusion he totally missed. Earth has only had portal tech for a handful of years yet the shop correctly identified the crystals and has stuff that requires them. The Vampire who made the system implied it may have been made a very long time ago... which means the Vampires could go to these other worlds long before earth as a whole acquired this tech. Also the MC should have asked the system about what the stats mean. And for Hand to Hand combat training that was a fighting style or martial arts system, not just for some special moves which consume tons of stamina while the rest of the time he is fighting like a noob.