[quote=@Windicator]
(is plural of a matoran, matorans?)
[/quote]

Short answer: No.


Long answer: This goes back to the early days of BIONICLE when LEGO was grabbing a bunch of words and grammar from the maori language, and in maori, like other languages with polynesian roots, does not pluralise by adding an s or anything else to the end of the noun. Instead,  plurality is determined by the other words in a sentence.

This set the pattern that would be continued on long after they stopped taking so much from Maori. Since we have one toa or six toa, one rahi or a dozen rahi, other, non-maori words like matoran also adopted this pattern. So, one matoran, two matoran, many matoran.