Well, Arte, the shop owner, references the fact that he did something bad that couldn't be forgiven in I think it was chapter 17? And since Eunwoo doesn't seem to remember him (I think bc of magic), why would he want to bring up something he feels guilty about and that Eunwoo could possibly never remember? If it was something that hurt Eunwoo, again, why would he want to bring it up? Sometime at the beginning he also talks about how he always puts Eunwoo in danger. Guaranteed, Eunwoo will find out eventually, especially with that one friend, Jisu, who looks like the shop owner. He seems really perceptive. I hope this helps :)
K thnaks
Bro the MC friend looks like the shop owner also why does the shop owner lie about meeting him and not just tell eunwoo
Also random stuff:listening toAteez:wave and ASTRO's :blueflame