i have a theory:
Tarduk is searching treasures in the deserts like all days, then, he sees that something is falling, when that thing falls in the sands. Tarduk comes to look at. then, he takes the the Mask thinking that is a gold treasure.
when he is going to Tesara in a Jungle Sand Stalker..
He is Atacked by Vorox and Zesk, Tarduk at the time falls scared the sand. While he sees at the Vorox they eat his Sand Stalker, the Zesk were approaching to him slowly.
In this moment, a light shine of the golden mask that the taked.
Leaving the mask to fall to the sand. The light towards more and more loudly. Tarduk hill his eyes for the fear.
While tape-worm his closed eyes, He listened to a very rare sound around him, on having opened his eyes, he saw that there was a Warrior of golden Armor. that he was coming from nowhere, but this Warrior was with the mask that the gathered from the sand.
The Golden warrior protected to Tarduk from the Vorox and to the Zesk. when these monster returned to the sands escaping of the Warrior.
This gentleman of gold helped Tarduk, The well-known Agori that the Warrior was speaking in another language. But then this Golden Gentleman started to speaking to him in his own language. " My name is A Mata Nui " the Gentleman said. " Can you take me to your Village? " Asked theGolden Warrior.
Tarduk and Mata Nui arrived to Tesara. Gresh and Vastus thought that Tarduk have contracted to a New Glatorian for Tesara.
But Mata Nui replied " I am not a Glatorian, Am a TOA "
Then blah blah Mata Nui explains what a toa is blah blah he tell them the story and legend of the MU and BLAH BLAH