A King of the Earth

From Kurosainosa:

The third prince of a beautiful country, Prince William, had stayed overseas as his mother was only a mistress. After that, his brothers had passed on and his father, the king was in his sick bed. So, Prince William was summoned back. Even though the life in the Palace is luxurious, the lustful desire of other noble family to snatch the throne was clear. That fateful evening, Prince William was shot and the one that saved him was a doctor as cute as an angel, Mizuki?