I am glad this is not BL, so all people can read this wonderfull story being not afraid because of the BL stuff.

the story is common but have a good concept. but the character development is really lacking here. character like jinwoo is too common in op, fantasy and action story. I don;t know why you call it unique

Bruh there's a lot of story like this, how can you say that unique. take a look at a lot of korean light novel, manhwa even anime or manga. there's a lot of story like this