Shinku Tsukihime

Tsukihime Shinku (月姫 深紅) is one of the main protagonists in Gakuen Sei Senshi Sailor Knight Series. She is also known as "Sailor Star Ruby"

Personality
Shinku is described as kind, heart-warming person who willing to risk her life to saves other people. She is kind to everyone no matter what position she's in.

History
At some point in her life, Shinku, along with Aoi and Midori, becomes Magical Girls known as Sailor Knight, which Shinku becomes "Sailor Star Ruby".

Sailor Knights
Shinku meets Utsuroi and invites him to plays tennis together. At the time, Utsuroi just knows that she is Sailor Star Ruby, and he wants to be the Demon King, he use her kind-heart nature as his advantage, and tricks her into his trap.

Shinku tries to transforms, but she got hypnotized before finished the sentence. Getting her memories erased, Shinku asks questions "who am I" like she is sleepwalking. Utsuroi replies that she is his "Shiba Inu" (a Japanese breed of hunting dog), which she believes him.

After the first hypnotize stage is finished, Shinku got kidnapped by Utsuroi, he takes her to his base and use full-brainwashing machine on her.

After that, Utsuroi erases Shinku's memories, and returns her to normal life, Shinku's heart will throbs whenever she talks to Utsuroi. He still can control her mind whenever he pleases when he triggers the keyword, which is [My cute shiba inu Shinku]. This time, Utsuroi commands Shinku to call him "master".

He releases her and erases her memories again, due to him wants to "truly" corrupts her without rushing.

He finally corrupts and transforms her into Dark Star Ruby.

Sailor Knights 2
In this sequel, Shinku returns as Dark Star Ruby, and helps her master to take down other Sailor Knights, completely destroyed them in the end.

Trivia

 * She is described by Utsuroi to be one of the most beautiful woman in the world.
 * She is called by other students as "Idol of the school" alongside her friends.
 * Utsuroi also described her as the most kind and innocent woman and he wants to always be like this, but his desire to becomes the Demon King leads him to brainwash her.
 * Due to her kind-heart and innocent nature, she accidentally tells Utsuroi about her fetish, which Utsuroi later use that fetish to brainwash her.