The Kanohi Komau was the Kanohi Mask of Mind Control. It allowed its user to make others do one's bidding, although it could only work on targets that had a mind (and therefore was ineffective against Vahki and some forms of Rahi).1
Notes
The Komau was the Noble Mask of Mind Control. It allowed the user to command others to do the user's bidding.2
The Kanohi Komau was the Noble Mask of Mind Control. It allowed its wearer to make others do his bidding.3
Komau were created from Kanoka disks with the freeze, weaken, and removes poison powers.4
It is possible that a Komau could work on someone wearing an infected mask or a krana, or a Rahi wearing an infected mask, or a Bohrok with a krana, provided that the user had sufficient willpower.5, 6
Hypnosis was capable of blocking out memories or creating false memories, but the Komau's powers were not hypnosis. The commands given by a Komau did not necessarily last when the mask was no longer in use.7
The Komau could not be used to defend against mental attacks. It was a purely offensive mask.8
A Noble Komau could probably not be used to control a Toa.9
The Komau could not be used to read minds.10
The Great Komau could drive mental lances into targets' minds because the mask allowed them to control the interpretation of nerve signals. This allowed the mask user to make anything their target experienced feel like pain.11
A powerful mind that resisted the Komau's powers couldn't use it to control the Komau user's mind; the mask only worked in one direction.12
The Great and Noble Komau differed in the duration of the mask's effect. The Noble form was probably limited in terms of the strength of will a user could overcome.13
The great Komau probably could not control Vahki, because they did not have minds, but programming.14
Toa Onewa would presumably not be able to mind control the Morbuzakh or Makuta, because they would have too much willpower.15