Fijians
The performer/dancer wears the mask at a ritual ceremony
the mayians do of corse
Africans for starters :P
the woyo tribe
which wrestler wears a mask
Hamilton has the masks custom made for him by a doctor in Warren Michigan who specializes in face masks.
called granada by albeniz from suite espanola
'The Moon Moth' by Jack Vance.
the animals the masks Vladek had to wear and Art wears at the back of the book the prisoner outfit Art wears in the Prisoner of Hell the doctor in the Prisoner of Hell that looks like Hitler the swastikas
None of the Teenage Mutant Ninja Turtles wear a purple eye patch. The turtles are known for their distinct colored masks: Leonardo wears blue, Michelangelo wears orange, Donatello wears purple, and Raphael wears red. If you are thinking of a character with an eye patch, it might be a different character from the TMNT universe, such as a villain or supporting character.
Slipknot and Hollywood Undead both wear mask. I'm not quite sure why, but I think they wear them just to make themselves look more interesting.
There is no way. Those who wears masks protect their faces and those who don't risk suffering further injury.