Thanks for the chapter!
So the reason elves only exist in Japan is due to surviving experiments to artificially increase magic power and potential. Also, the reason Kaguya was acting strange with the dull eyes was because she was following hypnotic orders. Usually hypnosis can't make a person do something that conflicts with their nature, but considering Nyarl has no human feelings of restraint or conscience towards methods used to intentionally break someone's ego combined with magic it's possible. Although if she can gather enough will with outside moral support she might be able shake free somewhat.
Btw, LN explains it better but Prometheus mentions that seems strange the security on the computer doesn't have any identity scanners like DNA, retina and fingerprints, just passwords. Also, MC had asked principal how was able to get in as the stigma analyzer lock on the single entrance only opens up to one person after reading their stigma. So without a stigma to examine it won't open. This was developed due to some Divas giving their contractors/hosts magic allowing them to trick conventional checks like fingerprints, retinas, facial recognition, etc. Also, while saying he doesn't need a face the pool of blood forming under the principal is due to him literally ripping the flesh off his head.