Anna Williams is a character in the popular 3D fighting game series Tekken. Introduced in the original Tekken, she is arch-rivals with her sister Nina Williams.
Background
Anna Williams is one of two daughters fathered by Richard Williams. As a child, Anna was taught to fight by her mother, and Nina by her father. While Anna was taught Aikido by her mother, Nina was taught and trained to be an assassin, and in doing so gained the affection of her father, while he would neglect Anna, thus spawning the epic rivalry that would ensue between Anna and Nina.
Tekken
Anna learned her Aikido techniques from her mother, who was a national Aikido champion. Her father, Richard Williams, taught Nina assassination techniques, but neglected to teach them to Anna. Due to the hatred spawned from the jealousy of Nina and her fathers relationship, Anna entered The King of Iron Fist Tournament in order to battle her sister.
Tekken 2

Anna as she appears in Tekken 2
After The King of Iron Fist Tournament, Anna became one of Kazuya Mishima's bodyguards (along with Bruce Irvin and Ganryu), and decided to enter The King of Iron Fist Tournament 2 in order to settle her score with her sister (who fired a machine gun at her after Anna planted a bomb on Nina's car), as well as to prevent Nina from assassinating tournament sponsor Kazuya.
In Anna's ending cinematic, she is taking a shower. She turns the water off, grabs a towel, and gets out of the shower. Nina walks in, and a few seconds later Anna turns her head around, and Nina takes a picture of her with a camera. Nina holds up the picture and laughs. There is a closeup of the photo before the cinematic ends. It shows Anna covering her breasts with her arms. Tekken 3
Nineteen years ago, Kazuya Mishima informed Anna that her sister was planning to become a guinea pig of Doctor Boskonovitch's "Cold Sleep" experiment. Despite their epic battles, Anna would miss her sister, and did not like the idea of aging while her sister did not. Anna decided to let Dr. Boskonovitch subject her to the experiment as well, asking that she be woken up at the same time as her sister. Sensing Ogre's presence, both Anna and Nina awoke nineteen years later. Although Anna awoke without any side effects, Nina had lost all of her memories, saddening Anna who enjoyed their sibling rivalry, but as an act of compassion decides to prevent Nina from becoming an assassin again. (It should be noted that while Anna had her own story and CG ending, she was only a pallette swap for Nina in the arcade version of Tekken 3, but becomes a separate character in the home version).
In her ending cinematic, Anna and Nina are laying on chairs at the beach. Three men come up to them. Two of the men are dancing while one flexes his muscles. Nina turns her head away. Anna is shown with two of the men, enjoying their attention. They walk past Nina and the other man. The other man goes with them. Anna and the three men walk away. Anna flicks her hair once and smiles.
Tekken 5
Anna had been leading a dull and boring life since the disappearance of her sister. However, all this would change upon receiving a phone call from Nina. The two met several days later, after being apart for two years. Upon seeing Anna's face Nina seemingly instinctively open-fired on Anna, and Anna retaliated, and a epic gun battle ensued for days, which resulted in a tie. The pair decided that they would settle their bout at The King of Iron Fist Tournament 5.
In her ending CG, Nina and Anna are hired to take part in a big Hollywood movie. They have a short, sword fighting sequence on a rooftop before facing off for the final blow. Lightning flashes and the sisters slice past one another. After a few seconds Nina emerges as the victor as Anna collapses to the ground. The director yells "Cut!" before beginning to complain that Nina and Anna aren't following the script. As he berates Nina, her armour begins to fall apart leaving her almost nude, and she desperately tries to hold it together. Anna rises from the ground and begins to giggle at Nina's humiliation.
Tekken 6

Anna in Tekken 6 gameplay
Anna was defeated during The King of Iron Fist Tournament 5 by her sister and arch-rival, Nina Williams. Nina sought revenge, not wanting their rivalry to end this way, but found that Nina had already gone into hiding. Upon hearing rumors that Nina has become Jin Kazama's new bodyguard, aligning herself with the Mishima Zaibatsu, Anna decides to join forces with Kazuya Mishima and G-Corporation, hoping to even the score at The King of Iron Fist Tournament 6.