Ganguro Girls

The Ganguro Girls are a trio of high school girls who bully Anri Sonohara. They are members of the Dollars, and after becoming victims of the slasher, they are also members of the Saika Army.

Appearance
Like other young women who dress in the ganguro fashion, the girls have tanned skin with contrasting light makeup and dyed hair. They sport a number of accessories and are usually seen in pastels, and they wear angel wings on their school uniforms.

Personality
The trio bullies Anri Sonohara on several occasions. They are hostile and dismissive toward people who appear passive, such as Anri and Mikado Ryuugamine, but when faced with someone stronger, such as Mika Harima, Izaya Orihara or Celty Sturluson, they show cowardice and often run away. When possessed by Saika, however, they display incredible strength, speed, and dexterity.

The girls usually hang out together in the city, and more than once have been seen out late at night despite being high school students. They are sometimes seen with Youko's boyfriends, including Hiroshi and Takeshi. When the girls hang out together, they are almost always on their phones, paying little attention to their surroundings, but they seem well-informed about the people and occurrences in the city. They also appear to take stock in popular rumors and have repeated them not only as fact, but as their own personal experiences.

Background
The girls attended middle school with Anri Sonohara and Mikado Ryuugamine, where they would bully Anri when they found her alone. Mika Harima used to come to Anri's defense and stand up to them. After Mika goes missing just before the start of the series, they continue to harass Anri, even though they attend different high schools.

Dollars/Mika Harima Arc
The trio first appears in an alleyway, cornering and bullying Anri Sonohara, backed by Youko's boyfriend Hiroshi. Mikado notices Anri and is working up a strategy to step in and save her without getting seriously injured himself when Izaya steps in, smashes Youko's phone, and shaves Hiroshi's head. The girls and Hiroshi run away in terror.

The girls are interviewed by Shinra Kishitani when he is on the street documenting sightings of the Black Rider. Akie claims to have seen it, but Youko does not remember, and Haruko tells her that the sightings are rumors. A tabloid writer later asks them who the strongest person in Ikebukuro is, and they tell him it is the Black Rider. They appear soon after in a building full of illegal immigrants and are nearly kidnapped before the traffickers decide not to take them, out of fear of having the Headless Rider come after them again.

Later, the girls are coming up from the subway when Mikado and the girl with the scar on her neck are being chased by the Black Rider. The pair runs down into the subway to escape and the trio surrounds Celty to take photos, unintentionally blocking her from pursuing them.

The next day, seeking revenge for her broken phone, Youko brings her boyfriend Takeshi to Raira Academy and waits for Mikado after school. While Takeshi is questioning Mikado about Izaya, Celty approaches him from behind and kicks him to the ground. Izaya jumps on him and threatens Youko, and she runs away wailing. She, Haruko, and Akie show up that night to the first Dollars meeting.

Saika Arc
One evening as Anri is walking home, the trio corners her again. Anri is blocking out their insults when she sees a red-eyed figure come upon them from behind and they are cut by the slasher. Youko, wielding a butterfly knife, is at the head of the Saika Army that appears in the park to cut Shizuo Heiwajima.

Trivia

 * Their names were revealed in "Durarara no Subete."
 * Ganguro are Japanese girls and young women who style themselves in the ganguro fashion and have dyed hair, tanned skin, and wear light, contrasting makeup and brightly colored clothing. The alternative fashion trend was started in Ikebukuro and Shibuya in the mid-1990s by young women who were rebelling against societal constraints and the traditional Japanese concept of beauty that values pale skin and dark hair. It is a form of self-expression that other styles developed from, though ganguro itself largely died out in the early 2000s. The term "ganguro" is derived from "gangankuro" (ガンガン黒), meaning "exceptionally dark," "burnt-black look," or "black-face."