This immortal king was extremely young, he must have been pretty young when he broke through to the immortal-king realm, thus retaining his looks. He was also different from the other immortal kings which sparred with Qin Wentian before. There was a streak of arrogance in the bones of this young immortal king.
Evergreen Yuhao's father is the blood brother of the Evergreen Immortal Emperor. He was extremely powerful but sadly, he died in the internal warfare of our empire back then. Hence, his Majesty has always felt guilt towards Evergreen Yuhao and hence, he spent numerous resources and sent him to all sorts of places for his cultivation.
But that side of the story is only what Evergree Yuhao know, the truth is that only a rare few knew of this because his Majesty back then issued an order not to spread it around. In the beginning, Evergreen Yuhao's father did fight for his Majesty but after that, he betrayed the empire for benefits. He was seen through by the White Emperor but because his Majesty was thankful for all of his prior contributions, his Majesty spared him and forbade anyone from speaking about it. At the same time, he treated Evergreen Yuhao fairly, but with a father like that, the son is so as well.