Riehchen was a zombie hunter stationed in Yu So-Jung's hometown. He and his partners would patrol the town after curfew to hunt any zombies that got into the town.
Riehchen and one of his fellow zombie hunters were keeping watch for zombies when Riehchen attempted to flirt with So-Jung, informing her that it was not safe for her to be out after dark. When she ignored him, he attempted to get her attention by informing her about a recent zombie attack on a student. So-Jung ignored this also, silently reflecting on her meeting with Sahu as proof that zombies weren't as violent as everyone claimed, and continued on to meet her ex-boyfriend Hyun-Su at her school.
Riehchen followed So-Jung to her meeting with Hyun-Su, where she was attacked by two zombies that had killed and were in the middle of devouring Hyun-Su. As they were preparing to devour So-Jung, Riehchen appeared, killing both of the zombies. However, they were quickly attacked by more zombies who were drawn by the sound of Riehchen's pistol. Riehchen returned So-Jung to the classroom, telling her to remain in the room until it was safe to come out. Riehchen then proceeded to slaughter all of the attacking zombies.
Upon returning for So-Jung, Riehchen, on a hunch, mentioned Sahu to So-Jung. Noticing her reaction to hearing the name, he deduced that she had met him, and began questioning her on his whereabouts, demanding to know where he was, and if Skull was with him. However, before Riehchen could get an answer out of So-Jung, he was shot in the head by Sahu, dying instantly.