@Background Pony #8611
Dark Fina is a rare and background character related to the first parts of the story… also there are Two different games in the Brave Exvius line..
One is a classic Rpg Gacha game with a story line related to Rain, Lasswell, Fina [and her darker half] and a rag tag bunch of friends.
Dark Fina is similarly dressed to this outfit but definitely not as revealing
Here is an example pic of her.
https://www.creativeuncut.com/gallery-34/ffbe-dark-fina.html
The second and newer game is called War of the visions… and I think Fina and Dark Fina might be cross over units.. but id never played that one so cant tell if shes part of the plot.. though im pretty sure shes not.

I checked Final Fantasy: Brave Exvius in the app store, but there’s no such game after checking it out

Have you ever played Final Fantasy Brave Exvius?
Her outfit and stance reminded me a bit of a character named Dark Fina.
Love this design, awesome work ^_

She’s beautiful!