A shapeshifting Needless with the Doppleganger ability that lets her change part or all of her body at will. Horrible at remembering names.
A part of the Adam project and as Gido claims that she was born for the purpose of having the capability to be pregnant with Adam Blade's child to reproduce offspring, since Adam's DNA is different from ordinary humans. Her last name was originally "N" due to the fact she is the 14th specimen ("N" is 14th letter), and was later derived as Neuschwanstein.
She was given the Doppelganger power by Blade making him unable to use it because he transplanted the part of his brain that learned doppelganger to her.
Her Doppelganger power is extremely strong however the weakness of this power is that she needs a lot of calories to use it. Therefore she often drinks an energy drink named 'Super Gel Dero Doro Drink', which contains 5000 calories. Using up her energy and not having anything but zero calorie Dero Doro to drink she is captured by the Simeon Girl Squad.
After being captured, a mind-control Needless named Kurumi used her like a marionette against her friends. Simeon also had a 'Super Gel Dero Doro Drink' device installed within Eve's body which gives her a huge boost of calories and eliminates her low-calorie weakness. The Needless controller was later killed, thanks to Cruz's wisdom, and Blade restored her mind by using the power and telling her to destroy the nano-bots that made controlling her possible so she could never be controlled again
Eve fights Saten only for him to throw the fight to her and in fact help her save her friends. When she ask's him why he claims its because he loves her.
After the Exsplosion Saten reappeares in front of a hospitalized Eve as well as the Blade faction and teased them about Eve's life threatening condition. He denies being the one responsible for Eve's condition and claims they are just paying her a hospital visit. The syringe he holds in his hand apparently is an antidote to Eve's poison. Blade engages Saten in battle, where Saten reveals a strange tattoo on his left arm. Using the 5th wave this tattoo activated he easily overpowers Blade. After Blade destroys the door linked to his memories, Saten desperately runs to Cruz who gets pierced by one of the shards and ends up being pulled into Blade's memories along with Cruz.
Cruz, Blade, and Saten went back to the church to find Gido covered in blood and Eve nowhere to be found until the group noticed a brain. Gido explains that the wound that Eve sustained had caused her body to melt leaving only her brain the same event that happened before entering Blade's memories.
Her fragment is 'Doppelganger', an ability which allows her to shape shift into anything (from a drill on her arm to other person's appearances as well as inorganic objects).