Fate and Gloria:

Fate is a rather badass villain, Negi's rival from the beginning of the series, and the only powerful Earth elementalist in fiction.  He also goes by Tertium, but it seems like Fate is what he self-identifies as.  Fate receives Sentou Scene 1 from FF1 as his song, because he's certainly involved in many fights.

Gloria is a princess who's willing to sacrifice her life in a ritual to save the world, but luckily doesn't have to as we end up being such a strong fighting force we just handle all problems with our fists.  She's very much a second Yuna.  The only problem is she's featured in Bravely Default II, which has awful graphics, but her actual personality is top class.  Gloria receives Silence of the Forest because that's the best song from Bravely Default.

While we're on the topic of unclear genders and Earth elementalists, I may as well add Crocodile to the wonderful fictional characters list.  And if I'm willing to add an ugly mean-spirited villain from One Piece, a cute and high-spirited villain like Ulti also deserves mention.  Crocodile gets Adel Desert for obvious reasons.  Ulti can have Plosive Attack because she's scary when angered.

Now that I've finished Amane's route and gotten to know Kurumi better, I think it's safe to add her to the wonderful list too.  Kurumi is very pretty with her highlighted hair, and the smartest girl in Japan, or close enough.  She's also extremely kind and affectionate to everyone around her.  I don't mind that she's got a gutter-mind, for a boy that's a bonus, and she's remained chaste until meeting Riku anyway.  She's adventurous and likes to try new things, whether social/outdoor activities or indoor games.  That fun-loving spirit is infectious to all around her, getting them to have a good time too.  Honestly the only fault I can find with her is how tall and buxom she is, the opposite of Noa's loli beauty.  Kurumi can have main theme (FF tactics advanced).  The song is made for her, cheerful, bright, but determined.