Kuroyukihime (黒雪姫, Kuroyukihime) is one of the main characters in the Accel World series. She is the current leader of the Black Legion, Nega Nebulus and was formerly known as the Black King (黒王, Kuroō), but hid after defeating the former "Red King". Her biggest ambition is to reach level 10 and meet the creator of the Brain Burst game, but to accomplish that goal, she has to defeat five other level 9 users who just so happen to be "The Six Kings of Pure Color", the leaders of the six most powerful factions in the Brain Burst world.
She is a very calm and patient person, a girl who constantly loves to drink tea, if it is in school or in a restaurant. She is not always that calm and patient as she can sometimes be rude, angry or jealous, even when some girls are starting to flirt with Haruyuki. She is also a girl who is wise with words and can talk manipulatively to another which they see it as annoyance. She is also a smart and clever girl, knowing the details about the "Brain Burst" game, since she was once known as the "Black King". The Brain Burst is not her only knowledge. She also has knowledge about wired connections or anything network related, as she can tell and give information in the smallest details. She even knows the steps of the networks that has been used.
Kuroyukihime thinks highly of herself also as a very intelligent person. At the time that she was called "Black King" she killed the previous "Red King" and also tried to kill the other members of the "The Six Kings of Pure Color" to become level 10 and find out who the creator of the Brain Burst game is. When she doesn't know someone's name, she will address them as "boy" or "girl", as she did with Haruyuki constantly when the two met and afterwards. She seems to be extremely skilled in playing simulation or any types of games, knowing that she defeated Haru in his own game by achieving more points then him. She also loves Haruyuki and their friendship starts to grow more to the point where she is pretending to be his wife. However, even that they show romantic feelings to each other, in the Brain Burst world, they become serious in fighting against others or giving each other information, but will change if someone tries to flirt with Haruyuki.
Kuroyukihime is a mysterious and popular student that also happens to be the Student Council Vice-President at Umesato Junior High School. Her Brain Burst Avatar is Black Lotus (ブラック・ロータス, Burakku Rōtasu), which she was a burst linker only when she was 8 years old. She formerly was the "Black King" but was driven into hiding after killing the previous Red King while she tried to defeat all other kings to reach level 10 and meet the person who created the game. She values Haru as more than a subordinate and is often the voice of reason to him when he is willing to go to extremes to protect her. Prior to her hospitalization, she confesses to Haru that she fell in love with him.
Holding true to being "the most beautiful girl in school" Kuroyokihime is a very attractive young girl, with a slender figure, large hazel eyes, and long flowing black hair. Her hair usually has two strands of hair extended from the top of her brow, resembling the antenna of a butterfly, When Kuroyukihime was hospitalized, she had her hair in a ponytail. Her wardrobe is usually her school uniform consisting of black tights, a dark green skirt with a brown trim, a navy blue blazer and a light blue bow tie. As she moves to her final year at school, her uniform alters to a red bow tie with all else being the same . It is extremely rare to see Kuroyukihime in casual clothes. It is somehow known that she prefers to wear black colored clothes.
Kuroyukihime is known to have an exquisite, original virtual character design. Her virtual character resembles that of a butterfly, and has been dressed with balled shoes. The overall look is black and while other parts have red or purple. Her avatar also carries an umbrella. This virtual character is the one she commonly uses whenever she has contact with other people and discusses with them about things that are usually happening around school, or she also uses it to demonstrate the world of acceleration, on how they can use it, or on how they can't use it.
Her "Burst Brain" character "Black Lotus" (ブラック・ロータス, Burakku Rōtasu) was once known as the Black King (黒王, Kuroō) but after she killed the Red King, she went into hiding. Black Lotus was known as a fearsome model before and after what happened to the Red King. However, she rarely reveals her Black Lotus form. The form of Black Lotus is more technical and robotic than her virtual character. It seems that she can only soar in a short length in the air instead of flying. The character model's color is black and purple. Black Lotus is unique since her limbs are blades instead.
There is nothing known about her abilities of her virtual character, or her brain burst character. What is only known is that her virtual character defeated Haruyuki's high score in a squash game. It is also known that her brain burst avatar, the "Black Lotus" is a powerful avatar, since she was able to defeat the previous Red King. Outside of her knowledge of the brain burst program and her virtual network knowledge, she has been shown to be a great strategist.
- It is still unknown what the real name of Kuroyukihime is. It seems that Kuroyukihime is her virtual character's name. She told her name to Haruyuki, but it seems that he's still calling her "Kuroyukihime".
- Her name "Kuroyukihime" (黒雪姫) literally means "Black Snow Princess".
- Kuroyukihime's Burst Link Avatar name is "Black Lotus", yet her avatar resembles that of a butterfly.
- She is born exactly on September 30, 2032 according to her forged identity.