Outlander: Blood of My Blood Episode 6 “Birthright” follows through on one of the show’s wildest swings to date. We’ve known since the Starz show’s very first episode that it’s rewriting everything we know about Claire Beauchamp’s (Caitriona Balfe) larger family tree, revealing that her parents Henry (Jeremy Irvine) and Julia (Hermione Corfield) did not die in a car accident as we previously believed. Instead, they traveled back in time to 1714 Scotland, where they met and interacted with Jamie’s (Sam Heughan) parents. However, the bigger shock might just be that Claire’s not an only child.

**Spoilers for Outlander: Blood of My Blood Episode 6 “Birthright,” now streaming on Starz**

Outlander: Blood of My Blood Episode 6 “Birthright” focuses on the pregnant Julia’s very dramatic labor, ending with the birth of her son. This means that, yes, Claire has a brother. But who is Claire’s brother? Is he someone we’ve met before? A character set to appear in Outlander‘s final season? Outlander and Blood of My Blood showrunner Matthew B. Roberts coyly revealed to DECIDER that “heads might explode” when he finally reveals who Claire’s brother is…

If you’ve been keeping up with Outlander lately, you’ll know that the last season of the hit Starz series ended with the implication that Claire and Jamie’s first born daughter Faith did not die in Paris. Instead, she may have gone on to give birth to Jane (Silvia Presente) and Fanny Pocock (Florrie May Wilkinson). (Which gets wild and incestuous when you remember that Jane slept with Jamie’s son William [Charles Vandervaart].)

Outlander Season 7 also briefly reunited Roger (Richard Rankin) with his time-traveling father (Nicholas Ralph) and featured a scene where Buck MacKenzie (Diarmaid Murtagh) shared space with his parents, Dougal MacKenzie (Graham McTavish) and Geillis Duncan (Lotte Verbeek). Basically, Outlander loves to further complicate its family trees with plot twists and time travel.

Given all that, it’s only natural that Blood of My Blood fans might be trying to connect Claire’s mysterious brother with a character we’ve already met in the main series. Is he simply the Simon Fraser we met in Season 2? Still living under the apprehension that he’s Lord Lovat’s (Tony Curran) child? Could Claire’s mystery brother could be former foe (and fellow mysterious time traveler) the Comte St. Germain (Stanley Weber)? There’s even a fan theory that Claire’s brother is Jamie’s older brother Willie, who died as a child. The idea being that Brian and Ellen adopt the wee lad.

When DECIDER got a chance to chat with Outlander: Blood of My Blood creator Matthew B. Roberts, he confirmed that his plan for Claire’s brother was baked into the DNA of the new series.

“It’s in the pilot. So that plan was in the pitch. So that’s how early that took place,” Roberts said. “I do have a plan where it’s going.”

Roberts is also well-aware that fans will be speculating away, saying, “I imagined there would be a million theories out there, which I love.”

“The plan that I have, I can always change my mind. So there’s that, too. So I want to keep everybody on their toes,” he teased. “But no, where I want to go with it, I think heads might explode…but I’m not going to tell you!”

Matthew B. Roberts currently has a couple of storylines percolating that could leave Outlander fans floored. Circling back to the main series, when we spoke last year to Roberts, he also promised that we’d learn more about what actually happened to Claire and Jamie’s first child Faith.

“I think you will visually see, we’re going to show you the story,” he said, of Faith. “We’re not going to leave it under the table. You’ll see the stories play out.”

So will Claire’s brother have something to do with Faith’s fate? Will he, per the seer’s prophecy, somehow become king of a united Scotland? Is Roberts setting up yet another potential Outlander spin-off about Claire’s time-traveling brother? Who is Claire’s brother!?!

The next episode of Outlander: Blood of My Blood comes out on Friday, September 12.