Kagari Shiina

Kagari Shiina (椎名 かがり, Shiina Kagari) is one of the characters of Steins;Gate 0. She is a war orphan and the adopted daughter of Mayuri Shiina in 2036 in the Beta Attractor Field.

Appearance
Kagari is a pale-skinned girl with long red hair, blue eyes and slender build. Although her similarities with Kurisu Makise are initially noted by Rintaro Okabe, there is no known connection between the two.

War
Due to the death of her parents during World War III in the Beta Attractor Field, Kagari became an orphan at a very young age. Since the registers of her family had been lost during the war, her true name was lost. She first met Mayuri Shiina during the year 2028 as she was working at a children's orphanage, and was given custody of the girl.

As the connection between the two grew, Mayuri went to eventually adopt Kagari in the year 2034, becoming her new mother and giving her her new name.

However, during the time Kagari spent in the orphanage, she was a victim of numerous experiments lead by Alexis Leskinen, who was trying to test Amadeus' capabilities as military weaponry, under the pretense that she was being treated of PTSD.

In the year 2036, Kagari was forced to travel back to the past alongside Suzuha Amane to escape an incoming attack. However, while they stopped in 1998 to stop the Y2K problem, Kagari's fear to lose her mother due to the worldline change caused her brainwashing to activate, causing her to attack Suzuha and escape. After that, she went to reunite with the Alexis Leskinen of that time and explained details about the future to him. She was taken by Stratfor to further experiment with her and given the codename "K6205", a reference to Mozart's The Magic Flute.

At one point, she escaped and met a young Okabe at a train station, teaching him a song. However, she was recaptured and this event was forgotten.

In some worldlines, she would eventually escape again in 2010, but this time suffering from complete amnesia. She was taken in by a temple, but believing that it was bad for the monks to be in the presence of a young woman, she was left in the care of Yanagibayashi Shrine. Believing Rintaro might be able to help her, Luka contacts him, but is unable to fully explain the situation. He later brings Kagari to the future gadget Lab and upon seeing Mayuri, memories of her childhood return to her, leaving her as a 22 year old with the mental state of a 10 year old.

Trivia

 * As with other elements of Steins;Gate 0, Kagari was first introduced in the Epigraph Trilogy.
 * The song that Kagari teaches Rintaro was taught to her by Mayuri who learned it from Yuki who learned it from Rintaro's mother who learned it from Rintaro himself. This creates a a situation resembling a causal loop with the song seemingly not having a proper origin.
 * While it resembles a causal loop, those do not exist in Steins;Gate due to how time travel is explained in the series. The song's true origin is most likely a prior Beta wordline that was overwritten after Kagari time-travelled.
 * One of the possible origins for the song is the music box gifted to Maho during the Vega and Altair branch of the Visual Novel.

Etymology

 * The name Kagari was given to her by Mayuri Shiina - a reference to "kagaribi（篝火?)", meaning bonfire -, with the wish that Kagari would be a shining light to everyone no matter how dark the worldline was.
 * Kagari's surname Shiina means "oak, mallet" (椎) (shii) and "name, noted, distinguished, reputation" (名) (na).