Theory but not actually a theory, anyone w braincells cud know this but I think the master they're reminded of is ja-in(mc)'s mom who actually passed away, he may have inherited his mom's prowess or smthg. That's y they can't recall meeting mc in their past lives but recall a memory of master who is wayy older and a woman. If they're the same age, it makes sense that MC's mom was their master
This ain't no school it's just a building with props where 30 yr old men come in school uniforms
No one can make me believe bald guy is 19