The territory of the Southern Guardian which was once as vast and equal to the other three directional guardians had shrunk to the point where it was just an area of merely called the South. Humans even the robots of this time had forgotten why it was even called the South at this point. They just assumed that it was called that because it was located in the South so whoever named the area was just being lazy or something. They were unaware that this area was under the direct control of the long since forgotten Southern Guardian Reva. However, he was inactive in his current state which did not prevent his natural control over his land from being displayed. All Guardian had passive control over a stretch of land that was just theirs no matter what they did and that area could not be claimed. The rest of the territory was what they needed to maintain and that was what they actively required to do so to keep it under their control.
Reva being unable to do this at the moment lost all his territory as Guardian minus what he just had regardless. The other guardians would attempt to take this land as that was not within their programming after all. Even if things had changed so that the true meaning of the Mecha Lord and their four Guardians were lost some things were just too hardwired into the system to ever be changed by those who were at the end of the day still bound by it. However, if the no robot could take what little land that Reva had left to himself then why did not the human do so. That was because they just could not as Reva's passive control over his unquestionable territory was littered with various robots that were almost Guardian level in strength and skill. There was no human that would be able to go about dealing with these robots normally. The robots were basically the remnants of the previous Southern Guardian's force that were not destroyed because of how close they were to their master. Even in his current state or possibly because of his current state he was not able to hold back the degree of power his passive control unleashed on those who were supposed to be under him. Cami might be his only subordinate but that does not mean he does not have others working for him under her as the remaining force had thinking gone as they were supposed to would have answered directly to Cami.
Because of what happened though these forces just roamed around aimlessly as they had no one to give them orders and the only ones they did have were the protect the lands of their master. That being the Southern Guardian and since no one knew who that was any more they were creatures almost no different than the ones that just existed without ties to anyone be it human or machine they were just there. Seemingly a part of the surroundings was natural as robots just knew they were not on their side(being one of the other three directions) and that was enough for them. Humans just saw them as robots to be avoided but slightly easier to deal with because they were robots without a master to guide them after all.
However, this all changed when they got the area under Reva's direct control in a passive manner. Though the effect itself was passive in nature thus how the lands were just under that Guardian's control without them having to defend it at least from other robots. However, the range that it covered was a passive effect that could not even be shrunk beyond a certain point. The output that showed off the intensity was under the Guardian's control as they had to tone it down others they would be unleashing the full intensity they could muster at all times. Whether this was effective in keeping the four regions balanced while they were in their inactive states or in keeping the humans away was unknown.
This was however how the humans were prevented from stealing the lands while there was no Mecha Lord without having to later pay a price for it. Sure they could take the land if they had enough prep time and a plan to maintain the lands that had taken for themselves. However once the Mecha Lord awoke and the Guardians did as well that land would be retaken and everyone within forced to flee, be killed, or be roboticized by the robot forces that reclaimed it. This was part of the cycle as humans were not aware they were just constantly losing the same lands repeatedly because just how the robots that oversaw everything had it set up. After all the humans only existed because they allowed them to after they lost the actual war between them. This was just how the world they had created after that win worked.
Because Reva did not control the output that he was giving out even if the range was at the barest of levels. The intensity was always at his max level thus what robots did just roam aimlessly around in this area was probably at a high subordinate level thus only those that were equal to that or greater. Those being subordinate of such a level, Guardians, Heroes, or people that could have become or eventually give rise to true heroes. So that is why the area was left alone by humans for the most part it was basically a death sentence as they were also smarter than robots of other areas so tired and true tactics that the robots were used everywhere else. These would not work on them at all in the slightest. In fact, it worked against whoever used them to the point where there were signs of why they should not ever do them. The weakness of those tactics would be fully exploited to the highest degree as they were even seen as just mere entertainment and nothing more.