Please don't pluarlize Bionicle words!!!!
That pretty much explains it. It's not cool. There is a Toa of Light, and there are six Toa of Metru Nui. Zaktan is a Piraka, and all the Piraka are evil. There are six Turaga that watch out for the Toa Nuva.
Generally, there are six of something and you don't need to add an 's'
There are six types of Vahki. A swarm of Bohrok are attacking the Koro. (that is a good examle!)
Don't do it.