Maky Kyung is a high school student who is a Hymu, someone who fights against the city's villains including the mutations that come from them when they are destroyed, sometimes in those fights he kills innocent people but not because he wants to or on purpose. He does it involuntarily and even apologizes a lot when he does it. He hates doing that when he's fighting and that's why he thinks it's better to stay away from the Hymu until he can fix that mistake in him.