The Physique Merit Laws are the rarest of all Merit Laws, because they can be created only by someone who cultivated respective Physique and the higher the level of the Physique the more difficult it is to cultivate it. The Physique Merit Laws for the Immortal Physique are much more valuable than any Immortal Emperor Merit Laws; even Imperial Lineages are craving them.
The first Physique Merit Laws were apparently created by cultivators with a natural born Physique with a trial and error method.
The different Physique Merit Laws for the same Physique can drastically vary from one another in quality, as they are based on respective cultivator's comprehension. For example, there are two known Physique Merit Laws for the Furious Immortal Tyrannical Physique — the Lion Monarch Tyrannical Immortal Physique Law and the Lower Tyrannical Immortal Physique Law. Lion Monarch's Law in considered to be much better, than Furious Immortal Progenitor's one, to the point that his descendants were ready to start a war with Lion Monarch's descendants in order to get it.