Empress

Empress (女帝) is the Stand of Nena featured in Part III: Stardust Crusaders.

Appearance/Personality
Empress is a stand bound to its own user blood, first appearing as a small drop of blood from Nena. Once the blood drop hits a person, however, the true stand is revealed. Empress starts as a small wart, similar to a bug bite, but gains a more humanoid shape as it grows. Unlike most stands, Empress does have a personality. It is a sarcastic, disrespectful, mocking stand, constantly insulting Joseph (the unlucky host), though it is also incapable of forming any complex plans, relying solely on its powers to survive. Despite its personality, it does serve Nena without other thoughts. It represents the Tarot Card The Empress.

Oddly, while this stand exhibits the traits of an automatic stand (extremely long range, strong personality) it seems to have the psychic physical connection to its user.

Ability
Absorption: Empress is a deadly stand, simply given its power. It first appears as a bug bite-like wart on the target's wrist. It begins to eat the person, slowly, growing a face, arms, and eventually an upper body. Later, it begins to eat outside items, such as chickens and fruits, in order to continue growing, all the while mocking its unfortunate host. Slowly, it kills the host, and then allows Nena to form a perfect replica of the dead being to wear as a skin to hide her true form. Despite its absorption power, Empress does not seem to have any ability to read its host's mind.

Trivia

 * In the film Army of Darkness, the protagonist Ash is infected with a demon that grows from his shoulder, first as an eye, and eventually as a wholly separate copy of him who names himself "Bad Ash".