Humanity's only survivor transcends time to save the world - Manhwa Recap

Ronan, one of the last soldiers of humanity, managed to take down the last giant with seconds to spare of his life. But unfortunately for everyone, this attack only was only a scouting party, as seconds later, countless giant's appear, ready to obliterate the world. Adeshan, his commander, gives him an orb that lets him transcend time and tells him he has one shot at saving humanity. Will he be able to become powerful enough?

Manhwa name : Academy’s Genius Swordmaster / Chapter 1-50