A gray, multicolored cat named “チコー” (also known as “Neko-san” or simply as “cat”) is one of the spirits that exists on ARIA.Four inhabitants of the planet were introduced and their relations to IA and ONE were revealed:
Planet ARIA is described as a world similar to Earth with various life forms that resonate and co-exist together, several of whom raised IA & ONE. In a series of YouTube videos dubbed ARIA STATION, IA and ONE introduced their home-world known as Planet ARIA. IA has little background, however she and ONE were given some background information for the ARIA - IA Musical & Live Show – performances. The design philosophy 1st Place worked toward was to make the voice simple and straightforward but easy to adjust and customize, letting creators create their own version of IA. IA is the first vocal in the '- ARIA ON THE PLANETES -' project.