Niji no Conquistador (虹のコンキスタドール, Niji no Konkisutadōru; Rainbow Conquistador) is a Japanese girl group formed in 2014. The group's themes are illustration, cosplay, and voice acting. It was originally managed by the illustration website Pixiv as a part of the Tsukudol! Project (つくドル!プロジェクト, Tsukudoru! Purojekuto) before passing to Dear Stage.
Source: “Karin Matoba”, English Wikipedia (CC BY-SA 4.0), excerpt
