Emi Sendou

The younger sister of Aichi Sendou. She behaves very much like a mother. She gets Aichi ready for school in the morning and makes sure he gets home at a reasonable time. She attends Miyaji Academy as an elementary school student. When she sees how Vanguard changes Aichi from shy to confident, she starts to worry less about him. Emi accompanies Aichi on most of his tournaments to support him and watch his well-being.

(Source: Cardfight!! Vanguard Wiki)