Ada Clover

Ada Clover is the older sister of Carl Clover and the daughter of Relius Clover. Due to one of her father's experiments, she was turned into the Nox Nyctores, Nirvana.

Information
Ada is Carl's older sister, and frequently doted on him when she was still human. Due to her affection, Carl idolized her, and frequently spoke highly of her to his friends at school (much to their amusement). One day, for reasons unknown, she agreed to become the subject of one of her father's experiments, although it is possible she was either forced or deceived into doing so. As a result, her body was fused into the Nox Nyctores known as Nirvana. Unfortunately, Carl bore witness to this depraved experiment and now seeks out his father in order to get revenge. Nirvana follows him now as his partner and weapon, acting upon his commands and protecting him.

In spite of losing her humanity and essentially becoming a puppet, Ada displays an unusual amount of sentience as Nirvana. There are many times where she will act on her own, usually when Carl is in danger or to attack a dangerous adversary. For instance, when Carl first confronts Hazama during the events of Continuum Shift, she attacks him without provocation. She does the same to Noel in another scene, surprising Bang that she could move without Carl's will. She also seems to frequently converse with Carl, who is the only one who is able to hear her, although many characters are skeptical. At the end of Carl's True Story, she acts on her own again in a confrontation against her father, fleeing the battlefield with her brother and Litchi. This surprises Relius, who briefly acknowledges her as "Ada" rather than "Nirvana," having previously only referred to her as if she was a thing.

During Chronophantsma, Relius states that he can "make Ada again", likely referring to transferring Ada's soul into another body. After Relius' defeat, Carl demands that he do so to which Relius agrees.

Appearance
As Nirvana, Ada has short light blonde hair and blank eyes, with a crack on her left eye; during the Dark War, she had normal eyes much like Ignis. She wears a purple dress with a white collar, a purple hat with a golden ring, separate sleeves, and longer arms that reach almost to her leg.

When she was human, she had slightly long hair, and wore a navy dress with vertical light blue stripes.

Personality
Before becoming a doll, Ada was a kind, calm, and cheerful person. She was always very kind to her younger brother and he idolized her. Supposedly, she is also a bit self-conscious about her appearance. After becoming a doll, she becomes lifeless but shows unusually high sentience, protecting Carl from anything that would be a threat to him sometimes without any provocation.

Trivia

 * Oddly, when Carl is victim of Amane Nishiki's Astral Heat, Ada does not appear; instead, Nirvana is shown as a plush toy.