A quiet bookworm in Usagi's class, called Amy in the English adaptations of the series. Highly intelligent, with a rumored IQ of 300, she can transform into Sailor Mercury, acquiring power over all phases of water. Ami's shy exterior masks a passion for knowledge and for taking care of the people around her. She hopes to become a doctor one day, like her mother, and tends to be the practical one in the group. Secretly, she is also a fan of pop culture and romance novels, and becomes embarrassed whenever this is pointed out.