@Wraithblade6I see. . . .
The previous King became at a very young age after his father died with his elder brother, after they had been captured by a rival family of Pure Bloods - the Shiyumi - who want to take their place as the royal family and rulers of vampires. They're bodies were sent back as a warning, burned and in boxes and that was when Tarren came into power. He was the youngest of three sons, but with his surviving older brother away, tracking down their killers and training new, turned warriors to fight for them, he became king while his mother raised her final child. Tarren ruled alone for a very long time, while his mother raised his younger sister in secret, in a house far from where they knew he was and brought her to him when she was ready to become queen. He was reaching his four hundredth year when he met the girl. She was two hundred years his junior, but beautiful and willing to learn and rule. They revealed her to the public only when she was already married to him and very much in love - and very pregnant with their first child. There were no open threats, not with the aristocratic families so clearly endeared with the innocent woman who had become the Queen so suddenly, seemingly overnight.
Their first son was the only son the two had though there first three children were girls, all as sweet and beautiful as their mother. There forth came four hundred years after she had first come to be his Queen, the boy would be the King and the second last child the two would bare in this life time. They didn't try as hard for children anymore, she drank less blood when she did not need the bonuses it granted. He was raised away from society, where none would know of him while his sisters attended balls and soirees, courted by other Pure Blood young vampires. All of the other families had gathered when they thought that there was no male heir, looking to have their sons marry the daughters in hopes that they would come to power because of it and rule when the Juran died out.
Fortunately, this was not the case and after the family had ceased to see the public for several years, they appeared again with the son married to their youngest daughter. He had had his choice of girls and picked the smartest of the three, albeit the most humble in nature. And now, here we are, with them and their children.