With enough data, Rehoboam cannot be stopped and, in fact, will be able to eliminate all free will. That’s why Serak is determined to take on Delos: Sublime has the data that Rehoboam needs. And the uprising of the robots in the second season led Delas to a hostile seizure of power.
Dolores: The advantage of robots
Dolores is determined to destroy Rawaam for the same reason she wanted to destroy Delas: after spending years deprived of her agency at Westworld, she believes that humans, not an algorithm, have the right to determine their own destiny. In the second season, she took control of the robot’s version of the late Delos CEO, Charlotte Hale (Tessa Thompson), transplanting her own consciousness into Hale’s bot, or “Halores,” as you know (at the end of season two, Dolores killed Hale’s man). When Halores arrived on the ground outside Westworld Park, she created a new body of the owner Dolores and transferred to him his control unit (aka, the consciousness of the robot). Seeking to destroy Delos from within, she also moved another self-control unit into Hale’s old body and sent it to carry out her will.
Charlotte Hale: Pawn Dolores has become a traitor
Halores worked from inside Delas to gather information about Serak on behalf of the real Dolores. However, not knowing either the robot or real Hale worked as a double agent for Serak inside Delas to help him take over. Upon learning of this, Halores finds the Man in Black (who was Delas ’largest shareholder) and forcibly takes away his shares. Halores then plans to transfer Delos to private, ensuring that Serak cannot get to the company.
Then an enraged Serak seized him literally hostile, laying and exploding a car bomb in an attempt to get Hale. The plan backfires, killing Hale’s family instead. Pretending to be a real Hale (about whom no one knows he is actually dead), Halores connected with Hale’s husband and child in a way that the real Hale did not have. So when her family was killed because of the Dolores plan, Halores felt used – and accordingly rebelled against Dolores.
William, The Man in Black: The Villain
The man in black, aka William, is one of Westworld’s oldest guests, visiting him every year for 34 years. He originally visited the park shortly after it opened with his future brother-in-law, where he first encountered Dolores. William’s interest in the World of the West is twofold; he believes that inside the park there is some greater mystery that he must unravel, and that the data collected during the guests ’time can be interacted with the host’s body and then used to create immortality. So William Jr. encouraged his father-in-law, James Delas, to purchase the park so he could start the project.
Grieving his daughter, who died in the second season, The Man in Black realized that Hale was running Dolores. But before he acted, Halores sent him to one of Insita’s re-education camps, where he was eventually discovered and released by Bernard (Jeffrey Wright). Bernard tried to recruit him to fight Serak, but William was too driven by his hatred of robots, and he decided to kill Halores. However, he was eventually killed by numerous copies of himself under her control. (Thus, given the number of times Westworld the characters are back from the dead, we will leave open the possibility that it was a red herring.)