Fire Emblem Heroes has already been getting some flack for their uninspired character design, and this is a good comparison of the changes made to Rhajat for Heroes. Her original design still has problems, primarily the nylon tech this fantasy country seems to have, but the new version (named Virghat) is just so much worse. From the wiki entry on Rhajat:
…It is revealed that her cold personality is a means to mask her loneliness due to being raised in the Deeprealms by herself.
I’d believe that description, given that this was her sprite in Fates:
She’s hunched over, her eyes are in shadow, and her arms are in front of and around herself protectively. But the Heroes design and posture? All I’m getting from it, is generic poker-faced cute caster.
Oh, and of course, there’s a damage sprite, as mentioned in the comparison image.