Album it's from: Fantasia of the Shades, by the Shades, for the Shades
Title: 夢見ること (english title: Dreaming)
Group: 回路-kairo-
arrangement: 毛
lyrics: 毛
vocals: 556t
original title: U.N.オーエンは彼女なのか？
source: 東方紅魔郷 ～ the Embodiment of Scarlet Devil
Released: Aug 14, 2010
Art source: https://www.pixiv.net/en/artworks/12731851
Translation source: https://en.touhouwiki.net/wiki/Lyrics:_%E5%A4%A2%E8%A6%8B%E3%82%8B%E3%81%93%E3%81%A8
I own nothing in this video. I just slapped it all together. Hope you enjoy ~