0-kill Assassine 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

The legendary 'Treasure of the Extraordinary People' has descended, and the demons in Huaguo are rampant, causing great suffering to the people. At this time, the 'Black Ghost Squad' appeared, whose mission was to defend humanity and exterminate demons. Xiao Tian, the leader of the seventh assassination group of the 'Black Ghost Squad', originally wanted to serve the country with all his heart, but he discovered that the organization had another hidden agenda behind the scenes, and he was betrayed by his teammates, falling into a desperate situation...