Parallel City is a Manga/Manhwa/Manhua in english language, Manhwa series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.nl fastest updating comic site. The Summary is

Can two people look exactly alike? Fear sweeps the city as people report seeing their own doubles. Then the disappearances start. Mere coincidence? Or are the mysterious twins harbingers of bad luck? Whatever they are, if you spot one, you better think fast!