Satsuki Asui

Satsuki Asui (蛙吹さつき) is Tsuyu Asui's younger sister.

Appearance
Keeping with her family's froggy theme, she has a tadpole-like appearance.

Trivia

 * Satsuki's name is written in hiragana it can also mean "the fifth month of the lunar calendar" meaning "may" sharing the month with her name also with Samidere.