The "Little Boy" is one of the very first hosts ever created and is a copy of a young Robert Ford.
He first appears in the desert of the Unclaimed Territories. The Unclaimed Territories (and eventually the former location of the Agave Plantation) is under construction for most of the first season. He is portrayed by Oliver Bell.
His interaction with the Man in Black in the canyon (the Man in Black was on his way from the prison to Pariah) could indicate that there is more than one "Little Boy" hanging around ready to pop up when someone needs directions, or some water.
The boy asks Robert Ford if he's lost. The boy says that his family is "on holiday" (in American English this is "on vacation") and that his father said he and his brother could do as they pleased. Ford says that his father used to say that "only boring people get bored". The boy says that his father says the same thing. Ford invites the boy to go on a walk with him and the boy accepts the invitation. (This could be seen as Ford using some type of command to order the host to accompany him. Ford does command the boy to hear an imaginary church bell, so the boy is highly open to Ford's suggestion.)
The boy fetches water for the Man in Black. The Man in Black decided against draining the boy of his blood to transfuse to Teddy, because the boy was "too small". (This host probably wouldn't have had as much blood as later generation host anyway, because it is the mechanical version.)
Bernard discovers the boy, "Robert", with the rest of his family (including the Greyhound, Jock) inside a cottage. They are all first generation hosts and are functioning 'off the grid'. Dr. Ford reveals that Robert is a copy of himself when he was a boy.
The boy tells Dr. Ford that he killed his dog, because "Arnold" told him to.
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