Aki is a teenager of average height. She has fair skin, brown eyes, and dark burgundy hair. Most of her hair reaches her chin, with two neck-base long bangs that frame her face.
After SAO, Aki has grown up into a rather beautiful woman. She has a voluptuous figure and has let most of her hair grow longer reaching her shoulders. The two long bangs that frame her face now reach her breasts.
Sword Art Online
As the Black Rose Witch, she wears a brown cape. Her face is covered by a white mask with several red lines on it, with three long bangs of her red hair coming out from each side of her head. The rest of her is body wears a dark red dress, with a belt on her waist where she carries her weapon and black fingerless elbow length gloves on her arms.
Afterwards, she wore a red outfit covering her body and a red chest plate with a black line in the middle. She wears a red neck choker attached to her outfit, and an emerald crested, golden cross-shaped medallion, as well as a pair of dark, elbow-length gloves with a pair of gold bracelets above them. Her stockings are the same color as her gloves. They are connected to her skirt and she wears red high heeled pumps.
New ALfheim Online
She is a Salamander, and keeps her SAO appearance, though her burgundy hair has grown longer, reaching the base of her neck.
Aki wears a white shirt with short, puffy sleeves and a high collar. Over that, she spots a low-cut red corset above a sleeveless magenta trench. She also spots a red neck choker and an emerald crested, golden cross-shaped medallion, as well as a pair of black elbow-length gloves with gold bracelets above them. Her stockings are the same color as her gloves and are connected to her black skirt. Her boots are black and high-heeled, with a golden base.
She is almost always seen wearing a long black coat, with golden and red details that spot flames designs on the arms and on the lower part. She carries her rapier on a belt slung at the back of her waist.
Aki has a very cold and distant nature to her demeanor, a result of the spent time being treated as a monster. She viewed everyone around her as her enemy and eventually stopped caring about other people's feelings. Aki's rage at the world continued to grow, until the moment she became the Black Rose Witch, where her hate and anger reached its limits, hiding beneath the mask to have vengeance to those that insulted or despised her.
Yet deep inside her heart, she is suffering due to she is not accepted and she cannot fully control her powers, a reason she assumed this mean and distant nature.
Very few is known about her life before SAO. She has an elder brother with whom she entered the game.
Aki survived SAO, but her brother didn't. Apparently, Haruka was killed by her.
Aki has shown a strong connection to Galant. She is thankful after he helped her gain acceptance of who she was, and also helped her to control her powers after he defeated Black Rose Dragon.
Haruka and Aki are twin siblings. They are very close to each other and spent almost all the time in the game together. Naoto left her once when she acquired her unique skill, the thing he most regrets. After she was defeated by Galant, he bowed to remain with him until both of them escaped from the death game. She couldn't keep this promise since Haruka was killed sometime afterward.
Her skill on battle is the greatest shown by any female character in SAO: PoA. According to Galant, her speed matches even Asuna's at the time of thrusting a rapier. She also has great agility and speed, making her even a match for the Slayer of Cerdic.
In SAO, she rather used her unique skill Demeter's Gift, summoning her familiars and monsters to face her opponents defeating or killing them slowly. In difficult situations or those that her rage overcomes her, she uses her ace and the most powerful of her monsters, Black Rose Dragon.
In ALO, her skill with her rapier has raised even more. Her fighting style relies mostly on speed, thrusting and cutting her opponent quickly and then avoiding attacks or parrying and then counter. She is quite precise as well, quickly inserting her blade into the narrow slits of the armor of a Legionnaire. She has also learned to wield daggers and uses it in conjunction with her rapier or as a sidearm in close quarters, or if her sword is knocked out of her hand or out of reach.
As a Salamander, she has also become skilled with Fire Magic. She relies mostly on Fire Spears or Fire Balls, to incinerate her opponents in the long distances. She has also shown skill in Water healing magic but to a short extent. She can only heal very superficial wounds. She has lost her ability to use Demeter's Gift since such skill is not in ALO's system, this is one of the main reasons why she learned Magic. She is still a Dragon Signer, but for some reason, she is unable to summon her dragon.