Laura

Laura is an anime - only character and a baobhan sith,  (pronounced baa'-van shee), employed by Incognito, who infiltrated the Hellsing Organization and tried to turn Integra Hellsing into a ghoul. Possessing great hypnotic powers, she infiltrated without suspicion by mentally convincing everyone (except Alucard and Seras Victoria) that she was Integra's non-existant sister. In what is widely considered the most risqué scene in the series, she hyponitises, partially undresses, and bites Integra on her right breast. Integra partially breaks free of Laura's hold and  realizes then that she has no sister. Laura then stabs Integra in the stomach with a knife to begin drinking her blood, but is soon dispatched by Alucard, who had been delayed in an encounter with Incognito.

Personality
Laura seems to be calm and stoic, as well as being deceiving. She easily tricked Integra into believing she was her sister. She seems quite risqué in behavior. For example, after partially undressing a hypnotized Integra, exposing Integra's brassiere and tries to seduce her by  biting and licking her breasts.

Appearance
Laura is shown as a young baobhan sith with long blonde hair and pale blue eyes. Like most vampires she has pale skin. She has red dots on her forehead and a red earring for fashion purposes. And like all vampires, she has fangs that are sharp enough to puncture the flesh of their prey. Along with her blonde hair, she also wears a long green dress, two key traits of a baoban sith.

Abilities
Hypnosis: Laura has the unique ability of hypnosis. She can control people and make them bend to her will and is also skilled in deception. With the help of her hypnotic powers, she deceived Hellsing officers, Walter and even Sir Integra herself into believing she was her non-existent sister. However, her abilities have no effect on vampires, as she can only use it on living humans.

Trivia

 * Laura took her name from the novel Carmilla, but Integra also addresses her as a baobhan sith. Upon realizing her identity, Integra refers to her as the Countess Karnstein, this being another reference to the classic vampire novel Carmilla.
 * Her name is actually the name of one of the two protagonists in the book.
 * A baobhan sith is a type of blood-sucking female fairy in Scottish mythology, similar to the banshee or leanan sídhe. Also known as "the White Women of the Scottish Highlands", they are beautiful seductresses who prey on young travelers by night.
 * In the Japanese version of the anime, this got rendered as "Buubanshii", which is part of the source for the confusion on her name.