The third season of Westworld has shown us that plenty of human characters have been replaced by some robotics hosts. However, there are also some characters from throughout the previous seasons that may have already succumbed to this fate.
Some of the characters of Westworld could have secretly have been host the whole time, or they could have replaced by technological species.
Logan Delos- Logan Delos one character who would never have been human, to begin with. We also know that Logan died of a drug overdose, after suffering from his relationship with his father and also the fame and his fortune that came with the Delos name.
Sylvester- Sylvester is also one of the two key medics that the fans saw throughout the show, his job is just to patch up the hosts after they have been killed or damaged. The assumption has always been that he was a human that does not want to get on board with Maeve’s plan.
Robert Ford- The character Robert Ford was killed at the end of season 1 dramatically, but the fan theories have always been there which suggests that he could be a robot. There are three ways to look at this thing. The first thing is that Ford is not dead at all and a host took his place in the shooting.
Felix Lutz- Felix has also the role of patching up all the broken hosts. There is an important personality difference between these two colleagues, however. Felix is a much more empathetic towards the character Maeve and he also supports the cause that they are fighting for.
Ashley Stubbs- This character was also left questioning his reality at the very end of the last season. The doubt was put into his mind about the legitimacy of his humanity. As he is one of the leading members of the security team, it would be a perfect sense to rumor human error.