Psymau's were developed by Tovun of the Mekrona, designed to subdue a subjects natural brain functions and force them into subservience. They achieve this by harnessing the power of a reverse engineered Kanohi Komau, a mask of mind control, retried from a fallen Toa defeated by Mortus in one of his many ritualistic duels.

In some cases psymau's can even be used to resurrect the recently deceased, though with limited cognitive ability.