Let's Break Down Everything 'Westworld' Fans Know About Serac's Mysterious Brother

It took five episodes, but Westworld Season 3 finally dived into the backstory of its villain, Engerraund Serac. After spending weeks hinting around the edge of who Serac was, and why he built Rehoboam, the series finally confirmed the details. Engerraund Serac was born in Paris. He and his older brother were playing on the city's outskirts when the nuclear devastation hit, and the two of them managed survive together. But fans have questions, starting with who is Serac's brother? Warning: Spoilers for Westworld Season 3 follow.

So far, Serac has barely appeared in person, other than to Maeve. Despite seeming to live in a mansion, and controlling Rehoboam, he's only ever been seen alone. Liam Dempsey Jr., for instance, refers to Serac has the co-founder of Incite, with no mention of anyone else.

But according to Serac's own telling of his history to Rehoboam, he was never alone. He wasn't the creative genius behind the machine's creation, it was his brother. His brother was the reason they survived Paris, and Rehoboam was his baby. It was their dream together to build a god to protect this world, but his brother was the one to make it happen.

Viewers also learned a bit about Liam Dempsey Sr., the father who was part of this team. In Serac's telling, Dempsey was a moron, a money man who threatened to shut down a project he didn't understand if it wasn't making him rich.

Serac's brother was the one who figured out how to quiet Dempsey down. They took $5 million of the company's money and showed him how they could predict and manipulate the stock market into turning it into $100 million in a matter of a week.

But Rehoboam's real mission, to both brothers, was its ability to weed out the chaos agents to come, to keep the world on a steady track. It identified the Hitlers and the Henry VIIIs before they could refashion the world to their liking with little regard for the mess and removed them.

But Rehoboam couldn't erase these people from the narrative. Instead, Serac rounded them up, keeping them locked away as Rehoboam tried to change their trajectory. Then one day, Rehoboam identified a chaos agent close to home. Fans have assumed this was Liam Sr. (Liam Jr. has all but accused Serac of murdering his father.) But it was Serac's brother, who Rehoboam revealed was plotting to murder Dempsey.

As Serac tells it, his brother's need to control the future began to drive him mad. The last we see of the elder Serac, he's been moved into the lab for study, in hopes one day Rehoboam could help him too.

But this story, told by an already unreliable narrator villain, leaves holes. It's not clear if Serac's brother is still alive, for instance. Nor is it clear if he's still locked away. And it is curious that when Dempsey learned of all this, Serac's response was to do as his brother had planned, killing Liam Sr. in a staged plane crash.

Is Serac's brother alive still? Is he in control? How is it that fans learned so much about Engerraund and yet come away feeling like they still know so little?