MTL - Be a Leader In a Primitive Tribe - Chapter 71

Song Yan, a senior high school student, lost his parents when he was a child. Before obtaining a mysterious and amazing ring, he has been often plunged into a vulnerable position and easily marginalized. However, his life is changed because of the cryptic ring.

- Description from Novelupdates

The moment when mercenary leader Kwang Hwi receives video game like abilities, the world is suddenly thrown into chaos. A thick fog envelops the Earth, bringing with it savage, otherworldly monsters. At the same time humanity has been rendered defenseless against this onslaught, as the strange fog turns most weapons to rust. With mankind spiraling towards oblivion, it is up to Kwang Hwi, with his new abilities, to save the world. Watch as Kwang Hwi leads his militia and becomes the last bastion of humanity. Will he be this world’s savior, or its conqueror?

The fiancée has betrayed, but how could she know that the man she looked down upon was in fact a prodigy with healing and martial prowess!