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|“||Border's gotten as big as it has because of our existence and Karasawa's hard work.||”|
Ruka Shinoda (忍田 瑠花 Shinoda Ruka?) is an Aristeran princess, a member of Border, and the older sister of Yōtarō Rindō. She is not related to Masafumi Shinoda by blood; rather, she was given his surname in order to pretend that she is related to him so that Border is able to shelter her.
Ruka has dark, medium-length hair that curves to the front, in addition to bangs.
Ruka is quite arrogant and has no problem informing people that Border's success is in large part due to herself. However, Rindō emphasizes that she is nicer than at first glance. She is also very protective of Yōtarō.