all the class 1-A were in the common room, until Aizawa arrived with two children of similar ages. One was Eri, and the other was a girl with pink hair and green eyes

Aizawa explains to the class that they will be taking care of Anya and Eri for a while. And when he makes sure that all the students understand, he takes Eri and leaves (he gave up on leaving his daughter with high school students)