Ha Ru is a handsome student that Dan Oh starts noticing and liking after he saves her multiple times, helping Dan Oh in changing her fate. He is a nameless extra in Secret that even other characters are not aware of his existence. Being the 13th student in the class roster, Dan Oh calls him Number 13 at first. Later on, Dan Oh names him Ha Ru which, seemingly like a coincidence, was also his name in his former role in Neungsohwa. He has been aware that he is a character in a comic book.
(Source: Wikipedia)
