I Am the King of Survival on a Doomsday Island

Earth is struck by an asteroid. There are no supernatural powers, no rebirth, and no golden finger. The protagonist starts with the strength of a king, yet still cannot escape the cruelty of reality. Besieged by various factions, he watches the brothers and women around him die or leave, while a traitor nearly kills him. This isn't a hot-blooded power fantasy where everything goes his way, but a struggle against the harshness of reality.