Koharu Nanakura is a main character in Aikatsu Stars! and a student at Four Star Academy, where she serves as an administrator of the Moon Beauty Class and later becomes student council president. She originally applied to the academy together with her childhood friend Yume, and the two share a dormitory room despite being placed in different classes. Koharu was first drawn to the elegant and beautiful Yozora after Yozora helped her when her glasses fell off, and this admiration inspired Koharu to join the Moon Beauty Class.

Koharu has a delicate and quiet nature, which contrasts with Yume’s energetic and curious personality, yet the two remain very close. She is gentle, sweet, and always hopeful that things will work out, often putting others before herself and helping in any way she can. Her easygoing and accommodating disposition makes her a natural peacemaker who seeks inner and outer harmony.

Midway through the series, Koharu leaves Four Star Academy to study at Venus Ark, where she works as a designer while continuing to pursue her idol dreams. During this time she still longs to reunite with Yume and later graduates from Venus Ark, eventually returning to Four Star Academy to assume the role of student council president and continue her activities as an idol. Her preferred brand is Romance Kiss, and she is considered a sexy-type idol. Throughout the story, Koharu develops from a shy admirer into a confident designer and leader, always holding onto her aspirations and the bonds she shares with those around her.