Zankoku na Tenshi no Thesis, usually translated as A Cruel Angel's Thesis, was released in 1995 as the opening theme for the anime series Neon Genesis Evangelion, performed by Yoko Takahashi. The song became closely tied to the series and to anime culture more broadly, returning in later Evangelion projects and covers, remixes and live performances. Its short, high-energy opening is now widely shared online as a shorthand for dramatic anime style, making it a familiar cue even for viewers who have not watched the full series.