|Voiced by|| Chie Matsuura (Japanese)|
Kate Oxley (Funimation)
Linna Sim (Hong Kong)
Eba Ojanguren (Spain)
|Age||13-14 (Estimation, around Natsumi's age.)|
|Species / Type||Pekoponian|
Satsuki, much like Natsumi, is heavily a tomboy. She plays many sports, much like Natsumi, and seems to have a mad crush on her. Satsuki acts like an average high school girl, showing herself to be very forgetful, as shown in Episode 82 where she mistakes writing a calligraphy character.
- Natsumi Hinata - Natsumi and Satsuki are childhood friends. She seems to have a mad crush on Natsumi. This is apparent in many ways, such as the overwhelming appraisal, and telling her that she can "find a better boyfriend, or girlfriend" than Saburo.
- Yayoi Shimotsuki - Childhood Best Friend. The two are always shown together, proving how deep their bond is.
- Mutsumi Saburo - Satsuki initially didn't like Saburo, due to Natsumi liking him, but after getting to know him, the two become close friends. Saburo even invites Satsuki to join him and Natsuo on a trip to a cafe.
- Koyuki Azumaya, Keroro and Momoka Nishizawa- Friends
Her name comes from the traditional Japanese names of the month of May (Satsuki/皐月) and December (Shiwasu/師走).
- Her friend's name, Yayoi Shimotsuki, is also formed from two traditional month names.
- Satsuki may be based off Natsumi's Friends.