Loki director Kate Herron and star Jonathan Majors on his pivotal character's wild debut

Warning: The following contains spoilers from the season 1 finale of Disney+'s Loki.

Like the Sacred Timeline, Loki's end point was determined from the beginning: The multiverse would be born after Loki (Tom Hiddleston) and Sylvie (Sophia Di Martino) reached the Citadel at the End of Time and met He Who Remains, the mysterious and potentially villainous figure who created the Time Variance Authority and lorded over the Sacred Timeline.

"It was always our North star," Loki executive producer and director Kate Herron told EW Friday morning, two days after the chaos-creating finale arrived on the streamer. "What happened [between] when they met him and when the multiverse was born was still on the table, that's something obviously me, the writers, Michael [Waldron, the head writer], and the studio discussed and worked on.... I think honestly, for me and the writing team, we were just like, 'Okay, we'll just keep assuming we're going to get to introduce him until we're not allowed to.'"

Thankfully, no one told them no. Thus, Loki's first season ended with the introduction of Lovecraft Country's Jonathan Majors as He Who Remains — a variant of Kang the Conqueror, the supervillain Majors will play in 2023's Ant-Man & The Wasp: Quantumania.

"We got to do it and what an honor it was to bring him into the MCU. It was a big secret to sit on," said Herron.

"It was one of those moments in one's life, depending on one's occupation, where you go, 'Ah, this is it. This is it,'" Majors told EW when we spoke to him for an upcoming piece about his Emmy nomination for Lovecraft Country. "'All the s--- you talked about wanting to do, [now] there's a door in front of you. Be brave, walk through the door, and leave it on the field.' That was my mentality."

Marvel Studios; Inset: Alberto E. Rodriguez/Getty Images

From Herron's point of view, the trickiest part about pulling off the He Who Remains reveal was casting the right actor, because this is the first time the audience would meet this pivotal character.

"[The character's appeal is] in the writing, in the sense that we want to know who is behind the Citadel and who could be there. I think the exciting thing was he tells this story about his past and who he is. For me beyond that, then, it's, which actor are we going to bring in? Because it's got to be an actor with presence that immediately grabs you, because not every actor can do that, and Jonathan is one of the best actors out there. The fact that we got him to do this, I was just so happy because I was like, 'We're gonna be in really safe hands now.' He just commands attention. That for me was the real key thing for me, just getting the casting right," said Herron. "I was so excited that I got to be part of the conversation about the casting of his character with the studio and Peyton [Reed, Ant & The Wasp: Quantumania's director]. It was a massive honor and very exciting, and he's just an actor that we all loved."

Once Majors was cast as He Who Remains (and Kang), Herron thought of a way to integrate him into Loki before we ever saw his face on-screen: Through the Time Keepers.

"Something that was really fun for me was we hadn't, for example, cast the voice of the Time Keepers yet, because you know Wizard of Oz was an obvious reference of ours. I was like, 'Oh, let's get Jonathan to do it, because he's an amazing character actor,'" she said. "We sent him the art of all the characters and it was really fun [because] he was sending us all of these different voices he could do for each character, which was great."

Marvel Studios

The other obstacle they faced was Majors' availability, because he was working on Netflix's upcoming western The Harder They Fall in New Mexico when Loki was in production. "That was the hard part: preparing [He Who Remains] while leading The Harder They Fall," said the Da 5 Bloods actor, who arrived on set for Loki's final week of production in Atlanta. "It was wild."

"We finished with Loki, Sylvie, and He Who Remains, and it was kind of beautiful in a way because it is also how our story ends. So we filmed with Jonathan for a week," said Herron, who held read-throughs with Hiddleston, Martino, and Majors via Zoom before they started shooting. "Working on He Who Remains, it was really interesting because I started production filming so much of the Time Theatre with Loki and Mobius [in the premiere], and I love how it almost starts with a conversation and ends with one with He Who Remains."

As He Who Remains, Majors was intimidating, for sure, but he was also charismatic, eccentric, and very funny. The actor loved playing the role because it allowed him to draw on the clown/commedia training he learned at the Yale School of Drama.

"There's more smiling in that one performance than there has been in my other performances combined. It's just what it calls for." he said. "I'm a classically trained clown. That's part of my training. I've been at it for a long time, and to be able to exercise that was a lot of fun."

Marvel Studios

For her part, Herron wanted to do everything in her power to give Majors the room to play, experiment, and forget about the schedule, and the actor took full advantage of that and improvised. For example, the moment when He Who Remains rattles off what his variants said to each other when they met for the first time — "'I love your shoes.' 'I love your hair.' 'Oh, man, nice nose.' 'Thanks, man.'" — wasn't scripted, nor He Who Remains dramatically standing on the desk at the end of his tale.

"He was never meant to get on the desk," Herron recalled. "That was the fun thing with the improvisation. [The camera team] saw him start to move, and Autumn [Durald, the cinematographer] was like, 'Okay…" and then you saw the cameras start to move; it was almost like a dance with him. But that was not planned. It just blew us away because it was just so cool. That was the fun thing with him: I love the way he brought movement to the character in different ways, because I think that was really important as well. Where are we going to go for that big energy moment? Where are we going to draw people in?" She continued, "I love the bit when he sinks into the chair and he's like, 'I'm old and I'm tired,' and you feel his frailness in a way, you feel his aging, [even though] he's obviously a young man."

"The things that come out that aren't scripted only come out because the script is the way it is, and the world is what it is," said Majors. "A lot of it was through collaboration with Tom, Sophia, Kate, and Kevin Wright, the producer. They really let me run. And that's the best thing you can hope for."

As of right now, Majors couldn't say much about how playing He Who Remains affected his performance as Kang in Quantumania, which is currently in production. "You take it a day at a time. That's all I would say about that," he said. "You take it a day at a time and clean your plate and see what tomorrow brings. See what the next story is, and then take it from there."

Loki will return for a season 2, but when? Only time will tell.

Check out our daily must-see picks — plus news, celeb interviews, trivia, and more — in EW's What to Watch podcast.

Related content:

• How the Loki finale sets up Ant-Man 3, Spider-Man: No Way Home, and beyond

• Richard E. Grant on alligator whispering and his pitch for a Loki spin-off show

• Loki takes over: Tom Hiddleston on his new tv series and a decade in the MCU