Final Boss of Guilty Gear Xrd: -SIGN-'s Arcade Mode.
She's more of a distraction used by the real villains of the episode, who are being controlled by the actual real villain of the series. She switches sides after her defeat.
The second Valentine, Ramlethal has deliberately been designed to be something of an unemotional, feral beast of sorts. However, she is more a blank slate than anything else. Most of her character development is learning how to process emotions.