BirthEditShe was found inside the abandoned hospital by Riku and hatched shortly after. Who created her by placing the cocoon in Amane's body is unknown. Over the course of the story she has been under Riku's care and is always by his side barring a few exceptions, and she grew at an astonishing rate anytime she encountered a Kanshu by absorbing the memories the held. Due to her two protectors' close proximity, Neene has started calling Riku "papa" and Rena "mama". Eventually, F.L.A.G. noticed this growth and brought her in. Karasawa Shirou then connected to her and caused an additional growth, allowing her to free herself and save Riku.
She's later taken by Shirou to restore Ende and later stop Ende's rampage. After realizing his feelings were for Amane despite her feeling being for him the most important thing, her last words were "Liar." She is seemingly killed in the aftermath.
Neene appears alive in Chapter 71 as the master of the black beast. Apparently she shares her personality with Amane.She reappears as the cute girl she was before after a few chapters.
When she was born from her cocoon, she resembled an infant between 1-2 years old. After receiving memories from a swarm of Kanshu that invaded the school she grew once again to roughly the equivalent of an 6 year old child. During her capture by F.L.A.G she grew once again to roughly an 12 year old child's height. After she reappeared in chapter 71 has grown to roughly the same age as Riku.
Despite growing at a rapid rate, Neene's personality mirrors that of every normal child. She is happy, energetic and often a source of humor throughout the series. She is very affectionate, and from time to time clingy, as shown when she first hatched from her cocoon and seems only to listen to Riku. As she grows, she outgrows this clingy persona and tries hard to be dependent on herself but she is shown, at times, to need help from Riku or Rena. Although a child at heart, Neene seems to possess an adult-like insight to the world around her and seems to be much more emotionally connected when it concerns Riku or Rena. Unlike normal children, Neene assimilates knowledge faster than a normal child or human as she seems to recall memory or analyse knowledge at a faster rate. Like the other Coffin Princesses she exhibits a vicious protective streak concerning her master, Riku, and has used her powers numerous times to save him. Unlike Ende, who developed at a much more fluid way in her actions, Neene is more clumsy and seems unaware how special she truly is. She recently has come back from her "supposed" death, and has acted more mature. She also exhibits an unknown violence when she orders the black beast to attack Riku's friends but has gained more elegance, and fluidity, in her movements.
As with all coffin princesses, Neene can create Kanshu like her sisters, but has only done it once to save her master, Riku, when he was fatally injured. In Chapter 72, she creates many black Kanshu and declares a war.
Neene can alter and absorb the memories of others.
Neene can produce a cage in order to defend or attack, such as creating a ball of light that erases everything that's inside it except what she wants, as well as alter another's C.A.G.E, such as allowing Riku to penetrate Takao's C.A.G.E, or turning Ende's into harmless pillows. She can also produce wings to fly.