In Season 1, Episode 2 of Loki, we are finally shown the Variant that has been creating trouble for the TVA in the Sacred Timeline. Who is this character supposed to be?
The actress playing that character is Sophia Di Martino. In the official credits for Loki S01E02, she's listed as playing "The Variant."
Within the episode, the character is repeatedly described as a variant of Hiddleston's Loki:
Mobius: Here's the deal. When we get out on the branch, we're not just looking for a Time Criminal. We're looking for a Loki. A variation of this guy. A type we should all be very familiar with, because the TVA has pruned a lotta these guys, almost more than any other Variant. And no two are alike. Slight differences in appearances, or not so slight. Different powers, although, powers, generally include shape-shifting, illusion-projection, and my favorite...
This brings to mind the female version of Loki from the comics, who, like "The Variant," wore a headpiece with horns.
However, the credits for the S01E02 Castilian dub list a character named Sylvie, right under Loki's name, which is where "The Variant" was listed in the main cast credits.
And as Derek pointed out, around the 20-minute mark in S01E02, we briefly see a file with the name Sylvie Laufeydottir printed on it.
Considering everything above, it seems likely that this character is meant to be a loose adaptation of the female Loki from the comics, given the distinct name of Sylvie Laufeydottir in order to better distinguish her from Hiddleston's Loki.
The first name, Sylvie, might've been borrowed from Sylvie Lushton, a human granted powers by Loki in the comics, and the MCU writers may've drawn on other aspects of this character for inspiration as well.
Cailey Fleming is listed in IMDB's full cast & crew credits for the show as playing "Young Sylvie," which may be a sign that we'll be getting some backstory on "The Variant's" childhood in a future episode.
She is, as confirmed by Tom Hiddleston, a variant of Loki.
Can you talk about working with Sophia Di Martino? Since she’s playing essentially a version of you, is there anything she borrows from your portrayal, and what are the odds that there’s some kind of deeper relationship between you two? Because I feel like it would be pretty interesting if the one person that Loki falls in love with is a version of himself.
TH: That would be interesting. I think the idea, it seemed so rich that Loki would be confronted with himself. Not maybe just in a metaphorical way, but in a physical externalization. I absolutely loved working with Sophia. She had lots of questions for me, and my experience of playing the character, and various things that I had found interesting in the long history that the character has been around in human consciousness. But what was so wonderful is that she authored her own character completely. She had all her own ideas and inhabited it in her own way. Then the joy was putting the two of them together and seeing how they react to each other. Yeah, there’s lots of opportunities in there.