Susan Heyward as Sister Sage on season five of "The Boys."

Jasper Savage/Prime Video

Warning: Spoilers ahead for season five, episode six of The Boys.

The Boys character Sister Sage has been quietly orchestrating her own endgame in the final season, but one major miscalculation just derailed her master plan.

In the fifth and final season of The Boys, Sage (Susan Heyward), the smartest person in the world, helps Homelander (Antony Starr) take control of the country as he sets out to be worshipped and embraced by the masses as the one true God. But in the background, Sage has been secretly pulling the strings and manipulating people in the service of her own goal: watching the world end from the comfort of a bunker, and then living out her days in peace, reading as much as she wants and not being pestered by anyone.

“I think when you’re wounded and alone and isolated and really disappointed by humanity, you can go two ways,” Heyward said. “You can go hopeful. You can search for that next person, that next connection that might be the one. Or you can go really nihilistic and think that no one's ever going to change. And I think one of the themes of the show is: do you become like the monster who hurt you or do you stay hopeful and connected to humanity?”

Although viewers didn’t find out Sage’s true angle until episode five, Heyward said that she got clued in around the time that her character appeared on season two of the college-set spinoff Gen V and “fell in love with a racist, brilliant man who felt he was better than humanity,” also known as Thomas Godolkin.

In stark contrast to The Boys character Hughie Campbell (Jack Quaid), an eternal optimist with unwavering hope, Sage has decided that no one is worth saving but herself, and Heyward enjoyed playing a character who sees the world that way.

“I don’t get chances to play that,” she said. “A lot of the Black women I know are some of the most hopeful, most communal, most revolutionary people I know. And when we're giving honor to that, that's kind of what we do. So the opportunity to play something else is really exciting.”

While other characters walk on eggshells around Homelander and pay the price for not being loyal to him, Sage has been actively conspiring against him, without fear of the consequences. In episodes five and six, she plots to prevent Homelander from getting his hands on V1, which would make him immortal like Soldier Boy (Jensen Ackles), his biological father.

To do this, Sage tries to instigate a rift between Homelander and Soldier Boy, and shifts her allegiance to work alongside The Boys. Then she sets up a showdown between Soldier Boy and his former teammate Bombsight (Mason Dye), who’s in possession of V1. After the two supes fight, they reach an agreement and Bombsight gives Soldier Boy the V1. Sage, meanwhile, is delighted that Homelander won’t get the serum because people are predictable, and she’s confident that no one hates Homelander more than Soldier Boy.

But in a surprising move, Soldier Boy hands Homelander the V1 and he promptly injects himself with it.

“I think in the moment that it happens, she completely glitches,” Heyward said. “Everything that she’s based her worldview on is turned upside down. She's used her ability to predict people to survive, to build her value to people who otherwise would probably kill her. So, I think it compromises her sense of identity, her sense of self and her safety.”

Heyward said that Sage has survived this long by being useful to her parents, Teenage Kix, Homelander, and now Butcher and The Boys. But Sage’s incorrect read on Soldier Boy, which has resulted in Homelander becoming immortal, is a significant blow to her confidence in her powers.

“Now that that’s on shaky foundation, I think she has to find a sense of value in something else, and that's a big challenge for her,” she said.

The first six episodes of season five of The Boys are streaming on Prime Video. New episodes release weekly on Wednesdays, culminating in the series finale on May 20.