Emi Sendou is first introduced in Episode 3. She is very much like a mother, like getting Aichi ready for school in the morning, and making sure he gets home at a reasonable time. She also has a tendency to overreact. She attends Miyaji Academy as an elementary school student.
She cares about her brother a lot and acts like his mother from time to time; often having to wake him up for school and worries about his well being. When she saw how Vanguard changed her brother from shy to confident, she starts to worry less about him though she still went with him to most of his matches to support him and watch his well-being. She doesn't know about Kamui's feelings for her and supports Nagisa's feelings for him. She supports everyone on Team Q4.
Due to caring for Aichi she is mature for her age, as well as intellgent and a serious student, as seen in both her card fight ability and her pushing Aichi to do homework with her. [Source: wikia]
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