Eve (Parasite Eve)

"Once again... the day for the mitochondria to be free has finally arrived!!!"

- Eve aka Mitochondria Eve

Eve, also known as Mitochondria Eve, is the titular antagonist of the action/horror RPG video-game Parasite Eve and it's 1998 manga series of the same name based on the 1995 Japanese sci-fi novel Parasite Eve (パラサイト・イヴ, Parasaito Ivu) by Hideaki Sena. She is a sentient parasitic life-form that believes it is her duty to produce a new evolutionarily form of life beyond humans. She has the power to mutate mitochondria, the base building-blocks of biological life-forms, this allows her to mutate and control nearly any living creatures but can do so easier to creatures that are governed by base instincts. She has a strong link with the heroine Aya Brea.

History
Eve's first incarnation in the game is within that of a young opera singer named Melissa Pearce. Melissa received a kidney transplant from an unknown donor, that donor was Eve's original host that she first began to develop within. By the time the kidney was transplanted to Melissa Eve had a chance to spread interactive influence through-out the entirety of the tissue.

Soon after the transplant Melissa became sick. Melissa's new lease on life was spent focusing on her career as a rising opera star, however she was terrified of losing her health during one of her scheduled performances and that she would be replaced. Melissa's doctor told her the illness was chronic and so he gave her several immunosuppressants, which she unquestioningly took rather than risk her career on a sudden turn of bad health.

The sickness was of-course caused intentionally by the mitochondria of Eve to encourage her to take the immunosuppressants which prevented Melissa's system from rejecting her new kidney but also allowed Eve to extend control over Melissa's entire system much quicker.

Chistmas 1997
On Christmas of 1997 Melissa's acting troop performed an opera in New York City in what seemed like the big event Melissa had been waiting for, tragically this would be Melissa's last night alive and her face would become associated with blood and carnage rather than with that of a rising star. During the performance audience and players alike began to burst into flames during Melissa's big solo.

After the solo and spontaneous deaths the few people that could, fled for their lives one of the few remaining people was an armed NYPD officer named Aya Brea who had come to the opera on her day off. "Melissa"'s powers were unable to directly affect Aya however they seemed to have inadvertently trigger something within Aya giving her enhanced abilities. Aya confronted "Melissa" on stage, finding the opera singer had even more radical powers like projecting what appeared to be laser blasts. "Melissa" soon found the fight was more trouble than it was worth and broke a whole in the stage floor, descending into the backstage preparation rooms and Aya followed.

In the lower levels rats began to miraculously mutate into man sized, skinless rabid monsters and started attacking Aya under Eve's influence. Aya fought off the creatures as they appeared looking through all the rooms for "Melissa Pearce". In her journey she found Melissa's journal where she chronicled her operation, the stresses of balancing her health with her shot at a major career boost and how she began to feel less and less like her self the more her body adapted to the new kidney.

Aya eventually made her way to the back room to find Melissa playing a piano in solitude in a zombie-like trance. Aya pointed her gun at Melissa and ordered her surrender however Melissa seemed less than concerned instead trying to maintain some degree of control of her body. Melissa's chants of trying to reassure herself of who she was quickly changed though, ending with her declaration of the name "Eve". "Melissa"'s hands broke through the piano keys and her entire body changed into an inhuman creature, effectively signaling the end of the life of Melissa Pearce.

Eve seemed to know Aya and asked her to join her waxing philosophical about a new stage of life, Aya's response... was with her gun and the two fought a second time, this time with Eve's powers much more matured than previously on stage as Melissa. Aya fought off Eve but Eve once again found that the fight was more trouble than it was worth and since she still could not exorcise direct control over Aya's cells she fled again this time into the sewers.

Aya pursued Eve into the sewers but could not stop her escape into the city at large, Eve tried to attack Aya on her trek out into the city but Aya was able to fight off Eve's assaults each time. Aya eventually lost Eve but would spend the remaining week trying to put down Eve while attempting to unravel the mysteries surrounding the nature of her powers and how she came to be. Each day Eve seemed to concoct a new strain of monsters and bazar plagues that killed people in horrific ways.

As Aya encountered more and more of Eve's mutants her inexplicable inhuman powers seemed to grow. Eve's ultimate goal was to literally give birth to the Ultimate Being. The birth drains Eve's form of all life in the process however Eve seems long since resigned to this fate.

Trivia

 * The title of Mitochondria Eve, is a legitimate term used for reference to the human race's common material ancestor. The game builds off this theory by naming Eve herself after this human.