So as we all know, when Mata-Nui went about his job fixing Spherus Magna, one of the things he did was unleash a wave of life energy which, among other things, cured those beings transformed by pit mutagen into their original forms, with the added bonus of becoming amphibious. Now the matoran of Mahri-Nui were originally from Voya-Nui but their settlement ended up sinking below the waves and trapped in a giant air bubble. This air bubble by and large saved them from being mutated severly, in fact the most the mutagen was able to to was transform their bodies into a form resembling their pre=Karzahni appearance. This makes me wonder, when Mata-Nui undid all those mutations, did the Mahritoran end up becoming converted back into their modified forms?
Well, we know Vican chose to keep his mutations. It’s possible the Mahritoran did too, since reverting to their voya Nui forms would make them weaker
As far as I know, Mata Nui only cured beings mutated by the Pit Mutagen specifically. Although not named, that’s certainly how it reads in Journey’s End:
The vast ocean of Aqua Magna felt Mata Nui’s touch as well. Underwater, plants flourished, providing a bounty for the fish that swam in the sea. The power of the Mask of Life touched even the twisted, mutated beings who lived in the depths, curing them of the worst of their afflictions while leaving them able to survive beneath the waves.
We don’t know that Mutran mutated Vican with Pit Mutagen (more than likely used viruses probably).
However, that is a good question about the Mahritoran. While they were mutated by the Pit Mutagen, they were only exposed for a very short time which allowed them to still breathe air. That alone makes me think it may be possible that Mata Nui did not change them back, again referring to the wording of Journey’s End. According to BS01, only Sarda and Idris (the two Matoran from the Karzahni set) are the exceptions that were exposed long enough to become water breathers, and Greg confirmed that Mata Nui cured them:
Well, he also cured the Shadow Matoran Mutran mutated.
Vican was an exception because he specifically wanted to keep the mutations
The power of the Mask of Life touched even the twisted, mutated beings who lived in the depths
I don’t think so; it says it cured even those in The Pit, which means it cured others as well. In addition to the Shadow Matoran that @Racie02 mentioned, I’m pretty sure that Metus’s reversal back into an Agori was caused by Mata Nui after the Battle of Bara Magna. (Which, funnily enough, I just finished posting about on BS01 before I even saw this.)