It was not easy to plant the Golden Mark and graft it onto someone else's body. The Golden Mark was the core mark left behind by the former Golden King. It was the proof of the existence of the Golden King.
To such an existence, the Golden Mark not only represented most of its power but also represented the essence of the Golden King.
Even if it was the mark left behind by such an existence, not everyone was qualified to inherit it. At the very least, if one's talent and potential were not enough to be recognized by the Golden Mark, the grafting could not be completed.
