Yumi Aizawa
She is the daughter of Shuichi Aizawa and Eriko Aizawa.
She first appeared at the end of episode eighteen when she asked her father if “off” means “vacation” and he starts to cry. After the time skip, she appears in episode 31 when Aizawa wonders if Light is Kira, saying that she was studying and tells him not to struggle so much.