Saki Mikajima

Saki Mikajima (三ヶ島 沙樹, Mikajima Saki) is the girlfriend of Masaomi who was hospitalized after being kidnapped by the Blue Squares. She has (until the end of the first season in the anime) an almost godlike idolization of Izaya, causing her to almost unquestionably obey him.

Characteristics
She has short charcoal hair (previously dyed brown) with light grey eyes. She usually wears a light pink cardigan, a white shirt, jeans and a necklace. In the past, she wore a black shirt with a white cardigan and pink skirt.

Initially, Saki is shown to be a very soft spoken individual and rarely expressed much emotion other than what was needed to get her point across. Much of this was due to Izaya who had practically brainwashed her into one of his many "followers" and used her in several of his plans. Because of this, she obeyed every order given to her without question, no matter how ridiculous or dangerous, such as faking a leg injury for a year in order to keep Masaomi under Izaya's thumb.

After finding the courage to defy Izaya for the first time, Saki begins to show more of who she actually is when not acting as someone else's puppet. She is very straightforward with how she speaks and rarely minces words, even coming off as blunt at times. Saki is also very perceptive, as shown how she is able to easily see through Masaomi's attempts to hide his loneliness after leaving Ikebukuro and how she is able to predict what he plans to do. Saki also appears to be extremely forgiving as she immediately returned Masaomi's affections even though he had essentially abandoned her out of cowardice during the gang war with the blue squares. According to her, she prefers to judge people based on their actions in the present as opposed to what they have done in the past.

Background
While the details are never given, it is implied that Saki met Izaya shortly after getting out of an abusive relationship. Izaya took advantage of Saki while she was still vulnerable and manipulated her until she eventually became a brainwashed follower. Under Izaya's orders, Saki made contact with and began a relationship with Masaomi Kida, the leader of a local color gang, the Yellow Scarves, with the intention of using him as another pawn. At the time, the Yellow Scarves were in a war with another gang, the Blue Squares, who were quickly taking over their turf due to using underhanded tactics.

Saki persuaded Masaomi to ask Izaya for strategic advice which gave the Yellow Scarves the upper hand, eventually causing Masaomi to rely more and more on Izaya's intel. However, Izaya also started aiding the Blue Squares as well to the point to where the two groups had almost wiped each other out. By this point, Saki's feelings for Masaomi had slowly become genuine love and thus wished to help put an end to the gang war so that Kida wouldn't have to suffer any longer. Izaya tells Saki that the quickest way to end the conflict would be to allow the Blue Squares to kidnap her which would most likely force Masaomi to disband his gang and back down.

Saki follows his advice without question but this only causes the battle to escalate as the Blue Squares intend to use her as a lure to kill Masaomi. Ran Izumii, the gang's leader, breaks Saki's leg to prove they mean business which causes Saki to pass out. She is eventually saved by Kyohei's Gang after they disagreed with Ran's methods and is rushed to the hospital as a result.

She initially believes Masaomi saved her but Izaya later reveals, while mocking him, that Masaomi froze at the last second before he could actually confront the Blue Squares. Izaya further orders Saki to keep up the facade of her leg being broken, even after it heels, in order to keep Masaomi under Izaya's influence. Saki would remain in the hospital for over a year until the second Yellow Scarves incident.

Yellow Scarves Arc
Masaomi makes sporadic visits to Saki in the hospital as the Yellow Scarves become more active. He tries to break off their relationship out of guilt but Saki refuses to believe it's what he really wants, claiming Izaya told her so. Saki takes a back seat to the events that transpire until towards the end. As she realizes the full ramifications of Izaya's plan, her love for Masaomi proves to be stronger than her devotion to Izaya. She contacts Simon and discloses all of Izaya's schemes which in turn causes Simon to seek out Celty to help resolve the issue. After Masaomi is hospitalized, she visits him, revealing she could still walk (although Masaomi had already figured that out a long time ago). Saki is amazed at having finally mustered up the courage to defy Izaya while Masaomi apologizes for not being able to save her in the past. He boldly reaffirms his love for her and the two tearfully embrace.. After Masaomi fully recovers, they decide to leave Ikeubukor and start new lives together.

Dollars and Blue Square Arc
After Saki and Masaomi left Ikebukuro, they started working as field agents for Izaya to support themselves. Their recent job was to gather information on Yadogiri Jinnai and the two of them were sent over to a very remote area to do so. Although Saki didn't mind it at all, Kida was very anxious and nervous through the whole trip. Saki lightly teases him about being to addicted to the internet and also questions why Masaomi doesn't simply just talk to his friends in person. As Masaomi tries to change the subject Saki deduces that he is lonely.

Masaomi denies it but Saki can tell he's lying. She states that even though she is Masaomi's lover, she can never be a "friend" to him in the sense that Mikado and Anri can. She says that if his friends are anything like he's described then they won't abandon him and even if they did, She would be there to give him a home to return to. With a newfound resolve, Masaomi packs his bag and goes to meet with Mikado and Anri.

Adabashi Arc
Saki receives an invitation from Masaomi to join the Chat Room, which she accepts. Her handle is simply "Saki."

Trivia

 * Like Saburo Togusa, Saki makes her first appearance during the Yellow scarves arc (Volume 3) in the light novels. In Saki's case, a few minor scenes concerning her (Izaya briefly visiting her in the hospital, for example) were moved to the Dollars and Saika arcs in the first season of the anime, likely to make the story flow a bit smoother.
 * She is the only person to have their real name as her chatroom name.