Will paths weren't hereditary.
Even if a man and woman of the same path came together to birth a baby, said baby wouldn't automatically be on their path.
As parents, they could choose to encourage their child to follow a true will path, or ingrain the doctrine of their will paths into them.
In the middle planes, the latter was always the case.
As soon as Kale could speak and think for himself, the Viscount had ordered the best scholars on their world to teach him the doctrine of the Redflame path.
After learning the path of the Redflame, Kale could swear it was only when he was in the presence of his father and older brothers that he felt true heat. Ordinary flames didn't affect him, he could swim in a pool of lava like it was water.
Though he felt like his father could turn him into ash if he so wished, it had never gotten to that level. He had never felt what he was feeling now.
True heat.
