Nina's personality remains monotonous yet sadistic when it comes to teasing Anna. Thus, she was unable to feel any emotion. Ironically, after her father's death, Nina was controlled by Ogre. The only man she had ever trusted was her father, who had died shortly before Tekken 2.

Her bitterness towards men could be a result of her defilation after Tekken 2. In fact, she had been drugged by an underground force when she was young in order to create the perfect assassin, regarding the chronology of Death by Degrees.

Nina persona seems to be cold and indifferent. During those years of Cryogenic sleep, she was impregnated without her consent and subsequently gave birth to Steve Fox (who first appears in Tekken 4 and onward). They are experimented upon for 15 years (this is the reason why they both remain so young for many years of the tournaments). During the end of Tekken 2, Nina and Anna undergo Cryogenic Sleep. She has a rivalry with her younger sister, Anna Williams. Nina has a lethal fighting style, consisting of throws, grapples, and holds. Nina Williams (ニーナ・ウィリアムズ Nīna Wiriamuzu) is a cold-blooded assassin that made her first appearance in the original Tekken game and has appeared in every Tekken ever since, being the only female character to do so.

Tekken 8 nina