Kyrexiel explained the situation as best as he could. To fully explain it though, he had to cover some related things about bloodline.
"If two bloodlines have a child, then the child will carry the bloodline of the strongest one. That's why powerful Clans like to marry only lower Clans below them so their bloodline won't be overshadowed. However, sometimes, two powerful bloodlines will combine to make a new one. And as you know, there's something about taking a leadership position with us, Rashaka; almost all clan leaders gave birth to only one child– they say it's evolutionn,n, so we won't tear the clan around with succession war.
"But it's not fixed. Some leaders gave birth to more than one child. Usually happens if the bloodline of their partner is equally just as strong or there's a potent bloodline passed along."