Original source (dead): https://wiki.famitsu.com/kairi/キャラクター一覧/【届ける想い】異界型ﾐｸ_-さいとうなおき-
Dead Kai-Ri-Sei Million Arthur wiki, so the image was most likely extracted from the game. Used in the game as the card "届ける想い" for their Miku collaboration.