Nine the Phantom
"Destroy it? Hehe... Don't say such idiotic things. When did I every say that I would 'destroy' the world? I only intend to 'end' this world... This worthless, lie filled world."
Nine the Phantom
That Bastard (AKA her father)
Konoe Ayatsuki Mercury (コノエ＝アヤツキ＝マーキュリー)
BlazBlue: Continuum Shift (non-playable)
Nine the Phantom (ナイン＝ザ＝ファントム), born Konoe Ayatsuki Mercury (ノエ＝アヤツキ＝マーキュリー) and historically known as the Great Magister Nine, was one of the Six Heroes, the creator of Ars Magus, the Nox Nyctores and a hailed figure across the world. She was the older sister of Celica A. Mercury, wife to Jubei and mother of Kokonoe. Nine was known for her incredible talent with both magic and sorcery which she used in great efforts to keep her family safe.
Nine, as "Me" ("わたし"), is one of the main protagonists of XBlaze Lost: Memories and first appeared as Phantom (ファントム) in BlazBlue: Continuum Shift. Nine was finally made playable in BlazBlue: Central Fiction where she is the final boss of Arcade's Act I.
Harboring burning fury at the knowledge of the truth of the world and using that power to end the world, she is the owner of a fearsome will and stormy temper. With her exceptional intellect and magical power, she created the "Nox Nyctores" and "Ars Magus." She dotes upon her younger sister Celica, and won't forgive anyone who would harm her. 
Belligerent, openly hostile to anyone except those closest to her. Nine is an openly rebellious woman who defies authority while expecting others to recognise hers. Her temper is always on the verge of exploding, and she is ready to let anyone know her feelings, unable to hide her explosive rage and sharp tongue. Nine has a habit of letting others know her superiority, and she openly demonstrates her power without thinking of the consequences.
Yet despite her temper, Nine has a mind sharper than many would initially believe. She is a thorough academic who has dedicated her life to sorcery, magic, Ars Magus, alchemy, and the creation of the Nox Nyctores'. Few can match both her intellect and cunning, and she is a revolutionary scientist who's discoveries, theories, and techniques have had a permanent change on the world. As a child, Nine was already considered a genius. She demonstrated a lot of patience and kindness towards Nobody and Es, going far out of her way to make their lives better even though they had not known each other for long.
Nine was unusually cruel to Kazuma Kval and judges people based on her initial perception of them. Although she has a good intuition of people, Nine does not readily change her opinion of anyone. Celica is one of the most important people in Nine's life, and she dotes on her young sister whenever she can. Nine will defy everyone and everything for those she loves, although for Celica, she will defy even her own daughter. She does not appreciate men approaching her little sister, thinking that they would manipulate her, and Nine has to keep a constant eye over Celica to make sure she is not in danger. Nine's relationship with her father, Shuichiro Ayatsuki, is strained - she hates him, blaming him for the death of her Mother, and knew even from a young age that he had plans for Celica in his experiments. Hatred does little to describe how intense her feelings towards him are.
Outside of her family Nine also deeply cares for one more individual - Trinity Glassfille, her best friend. Trinity is perhaps the only person that Nine will ever listen to, and at times, will even concede her own will to Trinity's. Throughout their friendship, Nine and Trinity have protected one another, but in recent years, this friendship has ended because of Nine's willingness to burn down the world for her family.
Nine feels as if the world is wrong because of the Amaterasu Unit and The Origin resetting time. Everything that Nine and her comrades fought for in the Dark War means nothing because it will all be reset. Upon learning this truth, she went so far as to begin creating a replacement "God". Knowing that Celica would meet her fate at the hands of Yuuki Terumi, her father unleashing the Black Beast, and the suffering of her family and humanity would all be repeated for eternity sent Nine on her mission to destroy The Origin and create a new world. Although her methods were questionable, Nine was ultimately trying to save the world once more, even though her true reasons were to save Celica, and she did not care much for the rest of humanity.
Powers & Techniques
Arguably not just one of the most powerful witches of her time, but one of the strongest sorcerers in history. Nine's sorcery is as aggressive as her personality as she focuses on delivering powerful spells with little casting time. Her arsenal of spells is vast, only being limited by her imagination. Nine furthermore has a unique yet deadly ability which she has no control over: she attracts seithr. This ability is only suppressed by her imitation of the Origin of the Grimoire which is her left eye, and absorbs the seithr around her.
In combat, Nine is able to rapidly deploy spells with casting time so tiny it almost seems like an instinctive reflex. She can fire a ball of light that explodes into a rain of bullets or fire gusts of wind so powerful that they can rend bone. If an opponent comes too close, Nine can generate lightning around her body to prevent them from coming closer. Teleportation is one of Nine's signature abilities although she initially struggled with using it at first, eventually mastering it over time and being able to teleport herself and others great distances. One of her other spells allows her to heighten her senses to the levels of beastkin, giving her excellent hearing and vision which far surpasses most humans. Although she seldom fights physically, Nine has enough strength to break doors with single kicks and lift fully grown men by their collars.
Although famously known for her belligerent sorcery, Nine is also an extremely capable scientist who created Ars Magus, Ars Armegis, and the Nox Nyctores class weapons. She was on the verge of creating the Burning Red Grimoire which would have allowed humanity access to sorcery, but it was never completed in her lifetime. Alongside her gifts with sorcery and science, Nine was accomplished with alchemy and magic, both being required for her recognition into the Ten Sages. The only Art which Nine is stated to have no mastery over is a Drive. This is reflected in gameplay where her Drive is The Abyss Diver but is not a reflection of her soul, instead being another way for her to cast numerous spells. In gameplay her spell arsenal gives her the most options of any playable character. Her spells here include summoning water, fire, and wind at basic levels, but her advanced spells include gravity manipulation, creating balls of electricity, creating reflecting mirrors, and summoning large tree roots to name only a few.
Nine's willpower has allowed her to endure the agonising nature of the Boundary and still retain her sanity. On top of her myriad of offensive spells, Nine is capable of others such as the Mind Eater, giving her complete control over a person's free will, something she used in great effect over Yuuki Terumi in the Dark War. She also has a contract with a demonic being called Hino Kagutsuchi which is seemingly under her complete dominion. Kagutsuchi is capable of being summoned to throw powerful kicks, punches, and generate large beams of energy.
Yet despite her incredible strengths, Nine is not immortal. Her blind love of Celica means that she is easily manipulated whenever her sister is involved, and can be distracted by Celica's presence; she is also easily irritable, and her rage can lead to mistakes. Furthermore, Nine's strength in her body created by Relius Clover severely restricts the magical and sorcery based abilities she possesses, and pale in comparison with her original body's power.
A close associate to the Imperator.
Nine's temporary form after she was sealed by Terumi in the Boundary... upon the Black Beast's defeat. Why she stays by the Imperator's side and does her bidding is unknown. 
Celica's older sister, and one of the Six Heroes.
She taught magic to the world, and helped develop its scientific hybrid, Ars Magus. Jubei is her husband, and between them, they have one very strong and powerful daughter: Kokonoe.
Like her belligerent personality, her magic is quite offensive and aggressive in its nature. She is determined in her ways, and loves her sister, which can sometime result in extremely reckless behavior. Her coffee's texture is said to change by the amount of sugar she puts in it. She also loves cats.
She can magic in its most pure form, which does not require the use of seithr. During the Dark War, she was admitted into the Mage's Guild as one of the Ten Sages at a very young age - a genius at her craft. She developed the Causality Weapons, Nox Nyctores, and led mankind to victory during the Dark War.
After the Dark War came to a close, she was killed by Terumi for 'knowing too much.' As of 2200AD, she been seen doing the Imperator's bidding as the mysterious figure, Phantom. 
Konoe A. Mercury
Celica A. Mercury's older sister, Nine. She's also one of the Six Heroes. 
Appearances in other Media
- BlazBlue: Central Fiction Consumer Edition Official Site (JP), Nine the Phantom
- BlazBlue: Phase 0, Chapter 5 - Sealed Green
- BlazBlue: Phase Shift 1, Chapter 5 - Night of Black Betrayal
- BlazBlue: Central Fiction, Library Mode, Character #028
- BlazBlue: Central Fiction, Library Mode, Character #030
- BlazBlue: Central Fiction, Library Mode, Character #059