In Marvel comics, Moon Knight has four personalities due to his dissociative identity disorder (DID): Marc Spector, Steven Grant, Jake Lockley, and most recently, Mr. Knight. Spector is the "main" personality — the one who created all the others. Yet, for Marvel Studios' Moon Knight, viewers were introduced to the hero through Steven Grant, a British museum-gift-shop worker who had no idea of his other identities.
While it was gradually revealed that Spector — a former mercenary and the original wearer of the Moon Knight mantle — was the main persona, Grant was still the show's co-lead, and for the majority of its first two episodes, the main protagonist. The choice was an unexpected twist to the hero's backstory (at least, for people familiar with the character prior to his live-action debut). Now, we know the reason behind that creative decision.
In Marvel Studios' Assembled: The Making of 'Moon Knight' (a Disney+-exclusive behind-the-scenes documentary about the show), Executive Producer Grant Curtis stated that Moon Knight Head Writer/E.P. Jeremy Slater (Death Note, The Umbrella Academy) wanted to have the focus of the first and second episodes to be on Grant, rather than on Spector (at the 10:14 mark): "Our head writer, Jeremy Slater, one thing he was very passionate about [was] really making episodes 101 and 102 Steven's episodes."
Slater further explained (at the 10:22 mark): "I always knew that starting the show with Marc was going to be very tough, because in our show, Marc is a very closed-off character. We would be fighting an uphill battle for the entirety of the series. I really looked at Steven Grant and I said, 'But that's a story I know how to tell.' Once you're onboard with who Steven Grant is as a character, you're in for the entire run."
Replying to Moon Knight co-director Mohamed Diab's comment about loving the choice to initially focus on Steven Grant, show co-helmer Aaron Moorhead said (at the 10:43 mark): "Starting with a mystery altogether, like, Episode 1 is a big question mark, which is, 'What's going on?" And sometimes, there's a temptation to get through it so you can see Moon Knight; you can see him beat somebody up. And we don't see that until the end of Episode 2. It takes almost the entire length of a feature film until you see the titular Moon Knight doing anything. And that was really exciting, when we actually had to play with mystery."
Executive Producer Brad Winderbaum added (at the 13:33 mark): "For me, the tone of the show is born entirely out of character. We're learning about the mythology of Moon Knight and the stakes of the story through a character who is as new to it as we are."
Starting out the show through Steven's point of view was smart, as it made him learning that he was an alternate personality stemming from childhood trauma a heartbreaking reveal, both for himself and the audience (again, to those unfamiliar with the character), as they realized the man they had been following was a mental creation.
What made it even better was the fact that, despite the revelation, the show never treated Steven as an imaginary entity. Instead, it allowed him to continue being a character in his own right, all the way up to the final battle when he and Mark fought in sync against Arthur Harrow (Ethan Hawke).
Creating Steven Grant
One thing was to choose which of Spector's personalities would co-lead the show, but another was to craft and mold said protagonist. In the documentary, Moon Knight star Oscar Isaac opened up about how he came up with Steven Grant's personality, stating the series initially portrayed the character as American, despite its main setting changing from the United States to England (starting at the 11:22 mark):
"I got sent some early drafts of a couple of the episodes, and I saw that the story had been transplanted from New York to London, but the characters were still written as American. But that got me thinking, 'Was there space to create a character that would be a good foil for what you expect from, like, a mercenary, tough hero?'
Isaac crafted Grant in his house, acting him out for his kids, which ultimately convinced him to commit to his version of the Egyptian-history enthusiast: "I thought, 'Well, since it's being set in London, what if Steven's English?' And I started coming up with this character around the house and doing it for my kids; and my oldest son just really started falling in love with Steven, and he would laugh a lot. So that made me feel like, 'All right, maybe there's something here. Maybe I'm onto something.'"
Turns out his children weren't the only ones who fell in love with Steven. Once filming began, the actor really connected with him, and found it enjoyable to portray him (from the 12:43 mark): "When we first started shooting, the first two months was all Steven. This process was one of completely falling in love with the character, particularly Steven."
This enjoyment led him to choose to stay in-character between takes, as that allowed him easy access to Steven whenever he needed to portray him:
"I can't remember the last time that I just loved being in this character. So, getting to set, I just wanted to stay in the accent and stay in the character. [...] I wouldn't describe myself as method at all. I just didn't want to be shy about it, and I didn't want to be second-guessing it. And so, for me, it was more about just like, 'Stay in it,' so that I can just trust that it's always there, and I can put my energy onto other things, like playing the scene and doing the things, and figuring out the blocking, and all that."
All episodes of Moon Knight are available to stream on Disney+. The documentary, Marvel Studios' Assembled: The Making of 'Moon Knight,' is also on the streaming platform.