I think that it's kind of difficult to say whether or not Khaldun believed that justice was transcendent. He makes a couple of interest points on the issue of justice and power, though. One of his arguments is that good and virtuous rule are the constructs of human action. Society and social orders along with their governments are created by individuals and human beings. Moving away from a divinely ordained existence, this suggests that justice might not be something universal and transcendent where individuals will automatically demand it, but rather is something that should be enacted as a part of the operational definition of good and virtuous leadership. Another similarly interesting claim along these lines is the idea that if one group conquers another, the conquered group will always mirror the former. The implication of this would be that if the ruling order rules without a sense of justice in its political design, then the conquered will mimic this and practice the same. This might shed some light on whether human nature would be sought. If justice to say is exposed and can be experienced, there is a greater chance that justice will be demanded.