Ethan, the Great Doctor
Ethan Miller, a waiter at a fancy restaurant, was suddenly kidnapped by unknown assailants and brutally beaten. After being rendered helpless, he was thrown onto the street in the pouring rain. As he felt he was about to die from the pain in his body, especially in his back, which was getting worse, he was rescued by one of the richest businessmen in the country.
Even more surprisingly, he was told that he was likely the heir to the dragon king's knowledge, which could cure all diseases.