@mobu nura
I'm not sure either, but I do know he's been hiding the fact from everyone that he's Korean (or reincarnated) so it could have just been his way of hiding that fact by pretending.
Unless I missed/forgot if he's revealed the fact he was Korean in previous chapters. But I'm pretty sure this has been something he's been keeping to himself.
So if what I remember is true, he wouldn't give himself away by going "Hello my fellow Korean's which my current countrymen have no idea about and is very specific about purging heritics where if I had knowledge that wasn't common I'd be a heritic and purged"
