The national guardian level was just a title, a title that some people would call out when they were bored. It was not a specific cultivation level, but one thing was certain — the only thing that limited national guardians from easily breaking through to the heaven-rank was whether they wanted to or not.
If one were to think about it in this way, in order to become a national guardian, one would have to be at the peak of the earth-rank on the path of cultivation. They would only be one step away from the heaven-rank, and could step into it at any time.
In other words, a national guardian must fulfill most of the requirements to break through to the heaven-rank, such as the unification of 10,000 Dao's, the comprehension of Dao laws, and the breakthrough of limits...