Kayano

Kayano (伽夜乃 Kayano?) is an original character introduced in the spin-off manga Boukan no Rebellion, where she acts as an antagonist.

Appearance
Kayano has long black hair, oval-shaped glasses. she normally wears a sweater vest over a standard school uniform. She typically wears an Upa mask when acting as a Rounder.

Personality
When killing, Kayano acts as if it was a game, acting like she was scoring points for brutalizing and killing her targets.

Due to her past experiences, Kayono is extremely cynical and has lost faith in people. She believes that people will always fight and hurt each other if given the chance. Because of this, in her mind, a totalitarian rule, such as SERN's is ideal because people are not able to fight with each other, forcing peace on an otherwise violent world. She is fully aware of how expendable she is to SERN, stating she is happy to die to preserve peace.

Background
Originally, she was a normal girl who was a victim of bullying. The only light in her life was the time she would spend at the orphanage and she was especially close to one of the girls, Hadzuki. One day, she got a recruitment message on her phone from the Rounders, but chose to ignore it. Shortly after, the orphanage was attacked and Hadzuki was kidnapped. Eventually, Hadzuki was located, but by then she had been mentally and physically broken. Kayano went to see her, but all Hadzuki could do was give her a a hug free of any warmth or empathy. Kayano had lost the bit of light in her life and this realization caused her to enter a coma. By the time she awoke, SERN subjugated the world. Kayano, seeing the world in a state of peace, believed that that kind of world was better then the one before SERN took over and anyone who wanted the world to return to how it was before was better off dead.

After this, she joined the rounders, gaining various physical enhancements with SERN's technology. She attempted to kill a young Suzuha Amane, but instead ended up killing Yuki Amane instead. 2 years ago, Kayano killed several of Suzuha Amane's allies. Her work for SERN was done while wearing an Upa mask.

Plot
The masked rounder attempt to kill Suzuha before she can use the time machine, but is foiled by Rei. She would go on to follow Suzuha into the past using her own time machine, a modified Chevrolet Corvette.

Seeing Suzuha, she follows her to the Braun Tube Workshop, claiming to be interested in a job. After arriving at the workshop, she moves to kill Suzuha, but is interrupted when Nae Tennouji hugs her from behind, mistaking her for Mayuri. Startled, she knocks Nae away. Yugo, furious, picks Kayano up by the collar, but before he can attack her, Suzuha, noticing Kayano seemed a bit unstable, interferes and pulls Kayano away. The two go to the park and talk for a while. Kayano question's Suzuha's motivations before attacking her. However, realizing that she hasn't gotten her strength back, Kayano retreats.

Kayano later texts Suzuha a picture of a tied up Nae, urging her to come to a certain location. After Suzuha arrives at the construction site, the two then have a knife fight. During the fight, Suzuha knocks off Kayano's mask, revealing her face, and Kayano reveals he history and why she wishes to keep the world under SERN's control in the future. Suzuha manages to create a smokescreen and uses the oppurtunity to rescue Nae and escape.

When Suzuha travels back to 1975, Kayano is already there waiting for her. Apon Suzuha's arrival, Kayano quickly attacks her, taking advantage of her injured state resulting in using the damaged time machine. Kayano then throws her off of Akihabara Radio Kaikan, resulting in Suzuha receiving amnesia.

After Okabe sends the d-mail, allowing Suzuha to use the undamaged time machine, she is able to properly fight Kayano on the roof of Radio Kaikan. Kayano destroys her own time machine explaining that as a rounder, she is disposable. Deciding the that two of them should be more discreet, they move their fight to another building. While fighting, they have another conversation about their motivations, causing suzuha to begin recalling their conversation in the other worldline. Taking advantage of her distraction, Kayano puts Suzuha on the defensive. However, once Suzuha gets the upper hand, she finds that she can't kill Kayano and instead punches her, turning their battle into a fistfight. While fighting, they continue to question each other's goals. Running out of strength, Kayano falls into Suzuha's arms and realizes that Hadzuki had been trying to cheer her up when she hugged her and that she had never tried to understand Hadzuki's intentions before dying.

Etymology

 * The surname Kayano means "nursing, attendant/attending, entertainer" (伽) (ka), "night" (夜) (ya) and "from" (乃) (no).