3CM Hunter is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Everyone in the world suddenly shrank to 3cm ...?! The consequence of this being everything in daily life becoming a threat, like rats... or even ants. A world where you can only rely on yourself. Will Baekhyun be able to complete his mission and save the world by using the unique abilities he gained?