Choosing His Path
So far in the history of the Human Race, there were only less than a hundred individuals that had the ability and talent to cultivate to the peak of the Second Realm and successfully ascend to the Third Realm, including Khal.
As for why only just a few humans were able to achive something that for other races was as easy as taking a stroll in the park, well, there were several reasons.
First and foremost, while Khal ascended the Thousand Path of Destiny with relative ease, it did not mean it was that simple. In fact, if one tried to ascend to the Third Realm one had to prepare himself or herself for the possibility of failing and ending up gravely injured or even worse dying!
For instance, if one with a weak body and physical resistance tried to ascend, it was very likely that when they reached the step that presses huge amounts of weights on their bodies it was very likely they will be smashed into meat paste as a result!