Tae Guk

During a family trip in a hot air balloon, a storm breaks out and causes the fall of Tae-eul, a young boy of 3 years in a lake called "Lake of the shadows." It is unfortunately bitten by a snake. A man living in an "enchanted forest" comes to his aid and managed somehow to save him. 10 years later, Tae-eul grew up and attended the village school of chaoring, where he trained in martial arts. But he eventually renewed several times without increasing his level, for lack of will. One day, Zin-lyong, a boy of 13 years, of a frightening level despite his age, arrived in Tae-eul's establishing after the death of his father. Tae-eul and Zin-lyong become friends and begin to train together ...

(Source: MangaUpdates)