There's just a little something you guys should be wary of.

or she is just fan service character

You would be giving the story writers way too much credit, even though you are only 69% convinced. She's just a classic boob-lady.

I hope she is.
Would be the funniest trap ever.
Btw I see what you did there with the % ( ͡° ͜ʖ ͡°)

EDIT: I will leave this here:
"Loki often runs afoul not only of societal expectations, but also of what we might call “the laws of nature.” In addition to the progeny listed above, Loki is also the mother – yes, the mother – of Sleipnir, Odin’s shamanic horse, whom Loki gave birth to after shapeshifting into a mare and courting the stallion Svadilfari, as is recounted in the tale of The Fortification of Asgard."

https://norse-mythology.org/gods-and-creatures/the-aesir-gods-and-goddesses/loki/

maybe, but the writers were probably trying to get in on the Fate series female gendering every historical/mythological figure train

I think she'll turn out to be a dragon. Aversa compares her to Grima in Dark and Darker and she was interested in ancient dragons during the Hoshidan Summer TT so I'm thinking she is, or is the daughter of, either Askr or Embla. I still think she'll be female though.

I mean... Imagine this... It's Xane. He was a freelance job character meaning he'd shapeshift the other ally units and take their stats and animations... So... What if it's secretly Xane?

Counterpoint: anime. Trying to understand or justify non-standard and/or logically impossible anatomy is an exercise in futility. If the Fate series has taught me anything, it's that 90% of characters, historical or mythological, are actually female, regardless of what their origin says. In Heroes' case, Loki is a girl (read: waifu).