This is Mavkhi, built on the Southern Continent near the end of the Matoran Civil War. A religious fanatic, as a matoran he would make regular trips into the Chamber of Life to pay tribute to Mata Nui, only to be turned around by Umbra. Umbra would want nothing more to do with the Matoran, but Mavkhi believes them to be friends.
One day, a group of warriors took up battle with Umbra in a crusade to obtain the graven image of Mata Nui stored at the heart of the landmass. Mavkhi witnessed the obliteration of one of these warriors at the whim of the idol, and understood this to be a grand act of tribute only Toa could perform.
Now a Toa himself, he spends his days performing deeds large and small. Hoping that one day, he too will be chosen as a lamb for the Great Spirit.
The hands are off of Leewan's Shapeways store, the mask is a pre-release model I was asked to show off.