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
Saki is a quiet, patient middle schooler who is quite trusting of other people, especially Izaya Orihara, whom she is very attached to and is like a guardian to her. She has followed ridiculous orders such as letting herself be abducted and injured by a rival gang in order to prevent people from getting hurt, ending the gang war. She is later shown to put a lot of faith in Masaomi and their love for each other, to the point of not caring if he hits on other girls because he will always find he loves her more.

She has short charcoal hair with light grey eyes. However, she originally had short brown hair, as shown in one of the opening themes of the anime and in flashbacks throughout the series.

Background
She started dating Masaomi when the Yellow Scarves were still fighting with the Blue Squares.

At the time, the Blue Squares did not fight fair, always picking fights they were guaranteed to win, usually when they had superior numbers and weapons. As the Yellow Scarves were in trouble, Saki recommended that Masaomi seek the help of Izaya Orihara. Although Masaomi originally didn't trust him, Izaya gave him sound information on the Blue Squares' hangouts and advice on how to fight them, which allowed the Yellow Scarves to gain the upper hand in the battle. This, combined with Saki's complete trust of him, led Masaomi to slowly open up to and become dependent on Izaya and his tactics.

Later, Saki was kidnapped by the Blue Squares as a means of getting back at the Yellow Scarves. They were hoping to draw out and kill Masaomi, in order to disband the Yellow Scarves and win the gang war. Masaomi repeatedly called Izaya for help, who never answered, and he was unable to rescue Saki. She was finally rescued by Kyohei Kadota and his friends, who betrayed the Blue Squares on moral grounds when they found out that their leader kidnapped and tortured a middle school girl because she was going out with Masaomi.

Although she was rescued, Saki was hospitalized for a year because of her broken leg. She was assumed to be crippled, and had to live in the hospital while watching visitors from her window. When Izaya showed her his call history, laughing at Masaomi's desperation in trying to reach him when Saki was kidnapped, she found out why Masaomi never saved her. This fact became Masaomi's greatest regret, and he later convinced himself that the reason he never went to save her was because his love for her wasn't real.

According to Izaya, this incident turned Saki into Masaomi's "god," becoming his past that he could never escape from, thus influencing all of his actions. When Anri Sonohara was injured by the Slasher, Masaomi's desire to save his loved ones led him to rejoin the Yellow Scarves in order to kill the Slasher. When he later found out the Yellow Scarves took in Sonohara on suspicions of her being the Slasher, the memory of Saki also led him to go back to the base of the Yellow Scarves in order to kill Horoda, the new leader of the Yellow Scarves, despite them wanting him dead.

As he was later hospitalized, it is revealed that Izaya told Saki to let herself be abducted by the Blue Squares because it would "end everything in the gang war." Although she was proud that Masaomi was able to overcome his fear and fight to save someone he loved, she thought him to be an idiot for running suicidally into the Yellow Scarves' base. It is also revealed that, despite her idolization of Izaya, her feelings for Masaomi led her to betray him, telling Simon Brezhnev about how he was manipulating people to create chaos in Tokyo. Both Masaomi and Saki also realized that their feelings for each other were true and she stops obeying Izaya, though she still thinks very highly of him and is greatful that to him for bringing Masaomi into her life.

Saki and Masaomi later disappeared together, because Masaomi's betrayal of the Yellow Scarves made it unsafe for them to stay in Ikebukuro. Their whereabouts are currently unknown.

Dollars/ Mika Harima Arc
Izaya checks on her and tells Saki his plan.

Yellow Scarves Arc
2 years earlier Saki meets Masaomi on the street telling him how cool Izaya is. Then they started dating during the rough times of the Yellow Scarves and Blue Sqaures gang war. One day she gets kidnapped by the Blue Sqaures and they broke her legs. Luckily, Walker Yumasaki catches the men on fire and runs Saki to the hosiptal with Kyohei's gang.

In the present Masaomi comes to Saki's room after a lot of years. Her legs were still broken. A couple days later Saki calls Russia Sushi and tells them what Izaya was planning. That same night she hears that Masaomi got hit in the head by a crowbar in the Dollars VS Yellow Scarve war. So she comes to Masaomi's room and tells him the truth. She said that Izaya told her to be kidnapped.

And that she needed to pretend that she still can't walk. Saki then kisses Masaomi. They leave Ikebukuro once Masaomi gets out of the hospital.

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

 * In her first appearance in the anime, her hair was light brown, then later on changed into darker shade of brown.
 * She is the only person to have their real name as her chatroom name.