There are the Sheet Music PDF and MP3 file of Ru's piano cover “新世紀福音戰士Neon Genesis Evangelion OP - 残酷な天使のテーゼ A Cruel Angel's Thesis (Lyrical ver.)”
Here is the YouTube video: https://youtu.be/sngEF3lrkeo
Piano Arranged and Performed by RuRu. (鋼琴改編及演奏: RuRu)