Mizuno Ami(Friend of Water) meets Usagi/Sailor Moon soon after transferring to Juuban Junior High School, where Usagi goes. She is very intelligent, though a bit of an introvert. She goes to a cram school and is rumored to have and IQ of 300. She always has been the calculating and rational member of the senshi, but is also a very caring friend. Like Usagi, she longs to protect those who are good at heart, even if it may mean fighting other senshi. Because of her quiet personality she is quite often overlooked as being the brains of the senshi, but is very sensitive of what others think of her. When an agent of the Black Moon tries to make her believe all her friends hate her, she could hardly stand it. However, knowing her friends well enough, she soon realized it was a trick and turned on the enemy, proving that her heart is just as strong as her brain.