- "I was given this spear to protect The World and that's just what I'm going to do!"
- — Kamui —
Kamui's online avatar was created as an homage to Albireo. Like him, she plays a Long Arm, has short black hair, plate armor, and eyes of two different colors. Her avatar resembles her real self. In the anime, however, she has short grey hair, and both of her eyes are red. When acting as a debugger, she adds a face visor and wields a copy of the Spear of Wotan.
Kamui is totally devoted to protecting The World. She sees Vagrant AIs as nothing but scraps of filthy data, and will stop at nothing to purge them from the system. She is completely zealous in her work, and does not tolerate mistakes made by her subordinates.
Kamui's player is named Saki Shibayama (柴山咲). She originally worked for CC Corp as an assistant to Kazushi Watarai. His love and desire to protect The World from harm had quite an effect on her personality. After Watarai left CC Corp following the Twilight Incident, Kamui took his place as a System Administrator and Debugger, becoming leader of the newly reformed Cobalt Knights.
Kamui is quite a mess in the real world. She is a chain smoker, and uses several anti-anxiety and anti-depressants such as Lexapro and Xanax to get through the day. Since smoking isn't allowed within the CC Corp building, she is forced to wear nicotine patches during the day. However, she seems to have broken that rule in Legend of the Twilight where she is seen with an ash tray several times.
Most of Kamui's hobbies are unknown, but she was addicted to The World when she was in college. This seems to have been one of the reasons she joined CC Corp after graduating.
Kamui appears in AI buster as Kazushi Watarai's assistant. Fresh out of college, she is still unfamiliar with many aspects of how CC Corp works. Watarai takes some time to explain what CC Corp used to be like when it was still a small company, and how most of the early development of the Japanese Version of The World was due to the eccentric programmer Junichiro Tokuoka. Though Kamui is impressed by his story, she doesn't quite grasp exactly what Watarai is trying to tell her, a fact that annoys him to no end. She confesses that The World doesn't hold the same appeal to her that it did when she was in college. However she is still interested in the game, as Watarai notices that she's carrying several printouts with fragments of the Epitaph of Twilight on them.
She later appears in the epilogue, hoping to impress her boss with the news that the One Sin was defeated. Though disappointed to find that Watarai already heard the news (as he actually witnessed the event) she is impressed with how he seems to keep on top of things that occur in the game. Unknown to her, she also brings him a clue that reveals Hokuto's true identity to him, that of the famous web poet W.B. Yeats.
During Wotan's Spear Kamui helps Watarai in his hunt for a strange Vagrant AI that appears as a floating cat (better known as Macha) and the enigmatic character Tsukasa. Using her powers as a system administrator and contacts with the player run guild the Crimson Knights she is able to determine Tsukasa's location, allowing Watarai to track him down inside The World as Albireo. After Watarai is attacked and rendered unconscious by a Twilight Guardian controlled by Macha, she is the first to find his body, and rides with him to the hospital. Though she believes his collapse was caused by overwork, she still follows his advice to leave Tsukasa alone, which explains the strange absence of system administrators during the events of SIGN.
This short story occurs shortly before the beginning of Legend of the Twilight. Kamui is now the leader of the Cobalt Knights, taking the same position that Albireo used to have. Kamui takes her new position very seriously, and is determined to live up to the ideals of her former boss. Trouble arises when Kamui is contacted by Magi about trouble with one of her subordinates. The woman in question, who plays the character Yukino has been seen with a Vagrant AI, despite the fact that such AIs are considered illegal, and should be reported to the Cobalt Knights upon contact.
Kamui travels to Yukino's location and finds her playing with the AI, a young boy named Rin. She informs them that Rin is in violation of CC Corp's policies and must be deleted. To Kamui's surprise Rin himself begins to plead for his own life. Displaying a surprising amount of intelligence for what she sees as nothing more than garbage data. However despite this Kamui deletes Rin, and dismisses Yukino from the Cobalt Knights. The experience continues to haunt her, reminding her of Albireo's experienced with the AI Lycoris. Nonetheless she vows to continue upholding the laws of The World, as the leader of the Cobalt Knights she can afford to do no less.
.hack//Legend of the Twilight
Kamui first appears with her knights, confronting Balmung and Reki about the recent problems on the server. CC Corp transfers the problem handling to the Cerulean Knights and they go on a mad rampage across town catching every character who as modified their character or has broken any of the rules in the user agreement.
The soon stumbled onto Komiyan III who rats Shugo out as the one who modified his character with a Data Drain. With Shugo as the new target, the Knights end up cornering him in a strange area where the AI Morti appears and destroys the area, sending all the Knights into a coma, except Kamui who is saved by Shugo at the last instant. After the incident, she takes temporary leave of CC Corp leaving the problem to Reki. She later tells Reki about the hacker kids and helps Reki build a virus to delete Morti. Seeing as the virus is unabled to be delivered in time, she makes the decision to fight beside Balmung to the end.
In the manga series, Kamui is portrayed as a very focused character, who will do whatever it takes to correct all the bugs inside of The World, which shows how much of a workaholic she is in real life. This fact is much pointed out by Magi.
She imprisons Shugo's party for having taken part in the criminal actions of Shugo himself, who had used his Twilight Bracelet to Data Drain Komiyan III, turning him into a fish-like character. Shugo takes full responsibility for this action and Kamui releases all of them but Rena and Zefie, who later on manage to escape prison.
In the Cathedral, Kamui and the Cobalt Knights corner Shugo right after he receives the Helba Key. Shugo and his friends escape, and Kamui pursues them. This leads to the final confrontation where Kamui's Spear of Wotan is shattered, and she begins to realize the true nature of The World.
- In the Legend of Twilight Anime, it is stated that Balmung and Kamui dated briefly in the real world and hinted that may still have feelings for each other.
- Tokyopop mistranslated Kamui as male in AI buster. She was the unnamed rookie Albireo talked to in the novel.
- In the original draft of Legend of the Twilight, Kamui was male, and also a long haired pretty boy like Balmung.
- Kamui claims to have graduated at the top of her class despite her obsession with The World at the time.
- In the Legend of Twilight Anime, Kamui's eyes are both brown, instead of being gold and blue.