Nini-tan, also called Sakura, first emerged in the desktop accessory program Materia before transitioning into an animated project. Within this narrative, she forms part of the trio known as the three maidens or three virgins, alongside Biscuit-tan and Chiyu. Together, they assist protagonists BB Runner and Ranna in confronting the antagonist The Master and his Junkies.

Physically, Nini-tan displays blue eyes and waist-length blue hair. Her narrative role minimizes verbal interaction, centering instead on visual presence and maintaining the trio's cohesive aesthetic.

A small, amorphous companion named Unyuu accompanies her. Nini-tan's origins trace back to early 2000s internet culture as a Ukagaka ghost within Materia software, informing her adapted inclusion without further elaboration on her background or development.