Emi Sendo is the little sister of Aichi Sendo. She is first introduced in Episode 3, and is also introduced to Vanguard in the same episode. 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, a girls-only private school.
In her first Vanguard fight in Episode 15, Misaki lets Emi use her Oracle Think Tank deck.