At the moment you can read the first 10 chapters for free of the version for 15year olds (for the 19+ you need age verification, which is complicated), for the rest you have to pay. You just need to use a translator since it is in korean.
https://ridibooks.com/books/5375000983
Is it Grayson and dain Story?
yes, it's Desire me if you can.
But it's a webnovel, which started on Wednesday, so it's ongoing and not completed.
got spoiled of what he's brother story gonna be like! now im excited for his and dain's story! wkwk!!! lcjsbshdbs it makes me want to read the novel grrrrr