Sphere (スフィア, Sufia?) is a J-pop idol unit made up of voice actresses who are all managed by Sony Music Entertainment's Music Ray'n subdivision, under the Lantis music label GloryHeaven. The group debuted in April 2009 releasing their first single "Future Stream". As all four are voice actresses, their music is frequently featured as theme songs to a variety of anime series, including First Love Limited, Sora no Manimani, Demon King Daimao, and Asobi ni iku yo!. The group features in the anime Natsuiro Kiseki, in which every member has a role as the four main characters.