Looking for a manga/manhwa

This guy and his family lives in an island (jeju?) with his family and then monster attacked. The brother and sister survived and hid in a bunker with other people. After days or weeks with no jelp coming from the government, they eventually ran out of food and had to go to the surface. The bunker gets attacked by the monsters, the brother was chased and cornered to a cliff and fell. He survived and was in a hospital with the help of the army. He was severely injured but then recovered quickly because he was infected? This power turns him into a monster/giant. Used by the army and turned him into a weapon, he then aids the army trying to exterminate the monsters coming through the airport. Thats all i can remember.