Sachiko Koshimizu

Hometown: Yamanashi Prefecture, Japan

Sachiko is a girl beaming with astounding confidence, priding herself in being the cutest. She doesn't consider herself a competitive person. However, she doesn't like to lose and doesn't easily admit to failure. When she's defeated as the boss of the Saitama area, Sachiko gives many excuses such as "I have a lot of homework to do so I'm going home".

From Sachiko's point of view, the Shining Aurora Traveler's Journal mobage event is a journey to let her fans know that the beauty of the aurora borealis isn't a match for Sachiko's cuteness. However, upon arriving to Norway, she decides that their rivalry should end in a draw, and turn into a dream collaboration instead. Likewise, her unit "Little Angels" featuring Ranko Kanzaki and Chieri Ogata, was born from Sachiko's intentions to overthrow the clione's status as the ice floe angel. Though Sachiko's self-centered remarks can be easily misunderstood, she doesn't make comparisons nor tries to belittle other idols.