men in black is william.This is how I understood, could be wrong.
There are two types of hosts, some are created by Ward and some are Arnold. According to Ward, Arnold was obsessed with giving hosts a consciousness which lead to a disagreement with Ward. So Arnold manipulated the original code of some hosts and put his own piece of code in them. Thatis why some hosts like Dolores and her previous Father hearing things in their head.
In westworld, they reuse hosts for new narratives they are wiping hosts memory of the narrative after a one and store them in a room until the hosts are needed to a new narrative. so hosts should not have a memory of pasts narratives. But due to Arnolds code manipulation some hosts are remembering past narratives. That's why they replaced Dolores's Father after a breakdown. That is why Dolores and Theodore attracted to each other.
Man in the black suit is a human, that is why hosts can't kill him. He is a member of the board of directors in Westworld organization. Still couldn't figure out why he's searching for the maze.
he wants to set free dolores.
this is why hes obsessed with dolores.



