Groan of Killer 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

Those known as "Grenimals" are grotesque creatures who endanger people's lives. In their search for more extreme pleasures, there are the "Lycanthrope," who cause disarray throughout the world, and the "Vampires," who despise humans as livestock and feed on their blood. The curtain opens on the ferocious battle between the Greminals and the executioners who face off against them.