Artist’s description from tumblr:

-*Sunset Shimmer*, a lioness with an unusual characteristic: having a mane. Given the nickname “Phoenix” from her circus handlers for her fiery and defiant personality, Sunset is headstrong and just as much of a leader as always has been. Sun once harbored very little trust toward humans, but spending time at the Sanctuary and being cared for by Celestia and the other handlers has slowly coaxed her out of her shell, and she has long since decided that not all humans are bad and that she’d give everyone a fair chance at proving themselves to her. She’s in the middle of a pride feud: half of the lions distrust humans by principle, where the other half think that while their previous handlers were cruel, it doesn’t by any means prove that all humans are terrible. And after the incident with the human teenager Starlight, tensions are running high as the pride is further divided.

Sunset has developed quite the bond with Starlight, which has furthered her belief that there is solid good in humans. And she will fight for that belief.