This image is from a trailer for an upcoming episode of Westworld. It shows William removing knife from its sheath on his belt. Notice the design of the hilt.
Now this is from an already aired episode, showing Ford handling a knife belonging to the Man in Black. Notice the same hilt.
Swarms of Westworld fans are debating on both sides of the theory that William becomes the Man in Black. I am just wondering when will the writers reveal the last secret they have to offer. Apparently, they have written the stories for at least 5 seasons of the show. Surely they would not reveal all their secrets right in the first season ?