"Why not the current King? Wouldn't it be better and safer?"
"It wouldn't be. Zhou Dong has been acting as the Duke of Country Y for the current King and Queen for many years, and that's why they trust him a lot. Although the King-to-be of Country Y has been of age many years ago, he didn't take over the throne because the current king and queen didn't want to burden him with the country's matters. However, the King-to-be of Country Y, as you might know, wasn't always with his parents. He was kidnapped when he was young and only returned many years later and the people who brought him back was none other than Mdm Xiao Lan Xi and Mr. Lu Qing Shi. This is the reason why the current King and Queen of Country Y dislike hearing people with the name Sapphire and Luke around as they felt that it was an insult to the people who saved their child."