So while it is possible that Teridax could not control Keetongu, I find it more likely he did not want it to be over so easily, and so used his other powers instead. Same goes for him controlling the Manas. Maybe he couldn't control all of them, but he is also so sadistic that he probably turned them on each other just for the laughs. Now that that is out of the way, your theory does make some sense, but there is a hole. Kraata and Krana do not form civilizations, yet they are not Rahi, and thus I would not think Rahi Control would work on them, although I do not believe this has been proven. Also, BS01 says that most Rahi do not have the willpower to resist the Mask of Rahi Control power, with possible exceptions of Krahka and Keetongu. So I'd say the answer might be in there, that the deciding factor is willpower and not intelligence. For example, gorillas are intelligent, but they don't really have the same willpower that we do in being able to push their bodies through pain to do things, resist a sort of mental invasion, etc. And it seems like possibly even Krahka and Keetongu wouldn't be able to resist it. I hope that all made sense VMN With Teridax and Keetongu, Teridax was trying to deal with TSO, Voporak, and Sentrahk. He was desperate to regain the Vahi, or at least keep it out of TSO's hands. As such, I don't think he would play around or take his time in dealing with Keetongu. Also, Kraata are like Krana in that they do not have individual minds/wills. They act for the good of the Makuta (which theoretically could order them to build a city). I consider them automatons rather than beings, and as such they would be outside the qualifications for Rahi. I should have made it more clear that I considered a species not to be Rahi if it was shown that members of the species (not necessarily the whole species) exist within civilization. Thus, a Matoran could live as a hermit in the jungle, but he would not be a Rahi, since members of his species do build civilizations. Of course, this would not include exceptional members of a species. For example, there could be a group of mutated Ussal Crabs which spoke and built a city, and were therefore sapient beings rather than Rahi. All Ussal would not then cease to be considered Rahi as a result. Finally, would Krahka be able to resist mental invasion if she shifted into something with telepathy or mental shields?